Polyalkenamer compositions and golf balls prepared therefrom

ABSTRACT

A golf ball that includes (a) a core comprising a center; (b) an outer cover layer; and (c) one or more intermediate layers; wherein at least one of the core, the outer cover layer, or the intermediate layer comprises a composition that includes (i) at least one polyalkenamer and at least one polyamide or (ii) at least one polyalkenamer. A method for making a golf ball comprising a core, one or more intermediate layers and an outer cover layer is also disclosed, wherein the method includes forming a blend comprising at least one polyalkenamer rubber and at least one polyamide; and injection molding the blend into a spherical mold to form the intermediate or outer cover layer. Also disclosed is a polymer composition that includes at least one polyalkenamer and at least one thermoplastic copolyamide elastomer.

This application claims the benefit of U.S. Provisional Application No.60/646,669, filed Jan. 24, 2005, and U.S. Provisional Application No.60/706,562, filed Aug. 8, 2005, both of which are incorporated herein byreference in their entireties.

FIELD

In one embodiment, the present disclosure relates to a golf ballcomprising a core, an outer cover layer and/or one or more inner coverlayers, and where one or more of the core, outer cover layer or innercover layers, comprise an injection moldable rubber composition. In onepreferred embodiment, a golf ball is disclosed in which the outer coverlayer comprises the injection moldable rubber composition. In anotherpreferred embodiment, a golf ball is disclosed in which at least oneintermediate layer comprises the injection moldable rubber composition.In another preferred embodiment, a golf ball is disclosed in which thecore comprises the injection moldable rubber composition.

The present disclosure also relates to a new method of preparation of agolf ball comprising a core, an outer cover layer and/or one or moreinner cover layers and where one or more of the core, outer cover layerand/or inner cover layers are prepared by injection molding a rubbercomposition. In one preferred embodiment, a method of preparation of agolf ball is disclosed in which the outer cover layer is prepared byinjection molding a rubber composition. In another preferred embodiment,a method of preparation of a golf ball is disclosed in which at leastone intermediate layer is prepared by injection molding a rubbercomposition. In another preferred embodiment, a method of preparation ofa golf ball is disclosed in which the core is prepared by injectionmolding a rubber composition.

In a further embodiment the present disclosure relates to a golf ballcomprising a core, an outer cover layer and/or one or more inner coverlayers, and where one or more of the core, outer cover layer or innercover layers, comprise a composition that includes at least onepolyalkenamer and at least one polyamide. In one embodiment, a golf ballis disclosed in which the outer cover layer comprises thepolyalkenamer/polyamide composition. In another embodiment, a golf ballis disclosed in which at least one intermediate layer comprises thepolyalkenamer/polyamide composition. In another embodiment, a golf ballis disclosed in which the core comprises the polyalkenamer/polyamidecomposition.

The present disclosure also relates to a new method of preparation of agolf ball comprising a core, an outer cover layer and/or one or moreinner cover layers and where one or more of the core, outer cover layerand/or inner cover layers are prepared by injection molding thepolyalkenamer/polyamide composition. In one embodiment, a method ofpreparation of a golf ball is disclosed in which the outer cover layeris prepared by injection molding the polyalkenamer/polyamidecomposition. In another embodiment, a method of preparation of a golfball is disclosed in which at least one intermediate layer is preparedby injection molding the polyalkenamer/polyamide composition. In anotherembodiment, a method of preparation of a golf ball is disclosed in whichthe core is prepared by injection molding the polyalkenamer/polyamidecomposition.

The present disclosure further relates to a composition that includes apolyalkenamer and a polyamide.

BACKGROUND

The application of synthetic polymer chemistry to the field of sportsequipment has revolutionized the performance of athletes in many sports.One sport in which this is particularly true is golf, especially asrelates to advances in golf ball performance and ease of manufacture.For instance, the earliest golf balls consisted of a leather coverfilled with wet feathers. These “feathery” golf balls were subsequentlyreplaced with a single piece golf ball made from “gutta percha,” anaturally occurring rubber-like material. In the early 1900's, the woundrubber ball was introduced, consisting of a solid rubber core aroundwhich rubber thread was tightly wound with a gutta percha cover.

More modern golf balls can be classified as one-piece, two-piece,three-piece or multi-layered golf balls. One-piece balls are molded froma homogeneous mass of material with a dimple pattern molded thereon.One-piece balls are inexpensive and very durable, but do not providegreat distance because of relatively high spin and low velocity.Two-piece balls are made by molding a cover around a solid rubber core.These are the most popular types of balls in use today. In attempts tofurther modify the ball performance especially in terms of the distancesuch balls travel and the feel transmitted to the golfer through theclub on striking the ball, the basic two piece ball construction hasbeen further modified by the introduction of additional layers betweenthe core and outer cover layer. If one additional layer is introducedbetween the core and outer cover layer a so called “three-piece ball”results and similarly if two additional layers are introduced betweenthe core and outer cover layer, a so called “four-piece ball” results,and so on.

However, the starting point and key to the performance of any golf ballis the nature of the rubber compositions used in the construction of thegolf ball, and in particular the rubber hardness, compression,resilience and durability. Most modern golf balls now utilize corecompositions made from synthetic rubbers based on polybutadiene,especially cis-1,4-polybutadiene. In order to tailor the properties ofthe core, the polybutadiene is often further formulated withcrosslinking agents, such as sulfur or peroxides, or by irradiation, aswell as co-crosslinking agents such as zinc diacrylate. In addition, theweight and hardness of the core may be further adjusted by theincorporation of various filler materials in the rubber formulation.Thus, there is a great deal of literature concerning such formulationchemistry and the variation of the rubber composition and degree ofcross linking such that cores may be produced with the requiredcompression, resilience, hardness and durability.

For example, U.S. Pat. No. 4,726,590 discloses a composition forone-piece golf ball cores having improved resilience. The corecomposition includes the following components: an elastomercross-linkable with a free radical initiator catalyst, a metal salt ofan alpha-acrylate or methacrylate, a free radical initiator catalyst,and a polyfunctional isocyanate.

U.S. Pat. No. 4,838,556 discloses a solid golf ball having a solid corecomprised of an elastomer or admixture of elastomers, at least one metalsalt of an unsaturated carboxylic acid, a free radical initiator, and adispersing agent. U.S. Pat. No. 4,852,884 discloses a golf ball coreformulation, which incorporates a metal carbamate accelerator. U.S. Pat.No. 4,844,471 discloses a golf ball core composition including dialkyltin fatty acid. Finally, U.S. Pat. No. 4,546,980 discloses a golf ballcore, which contains two or more free radical initiators, at least twoof which exhibit a different reactivity during the curing process.

Typically, the most common method for preparing and crosslinking thepolybutadiene in such cores employs a compression molding process. Thischoice of molding method is dictated by the relatively high viscosity ofthe base polybutadiene at the crosslinking temperature, which mustroughly correspond to the decomposition temperature of the chemicalcrosslinking agent. In view of the relatively high viscosity of cis1,4-polybutadiene at the typical decomposition temperature of mostcommercially available peroxides, a compression molding process is themost commercially viable process for such core preparation. This processis preferred for such high viscosity compositions, as it does notrequire the material to flow into the mold; rather a slug comprising themixture of polybutadiene, crosslinking agents, fillers and any otheradditives are placed in the open mold halves. The mold is then closedand the materials subjected to a molding cycle in which heat andpressure are applied while the mixture is confined within a mold. Thecompression and heat decompose the peroxide and/or other crosslinkingagents, which in turn initiate cross-linking of the rubber. Thetemperature, pressure and duration of the molding cycle, in addition tothe nature and relative amounts of rubber crosslinking agents and otherfillers and additives, can all be independently varied to control theresulting core properties.

After core formation, the golf ball cover and any intermediate layersare typically positioned over the core using one of three methods:casting, injection molding, or compression molding. Injection moldinggenerally involves using a mold having one or more sets of twohemispherical mold sections that mate to form a spherical cavity duringthe molding process. The pairs of mold sections are configured to definea spherical cavity in their interior when mated. When used to mold anouter cover layer for a golf ball, the mold sections can be configuredso that the inner surfaces that mate to form the spherical cavityinclude protrusions configured to form dimples on the outer surface ofthe molded cover layer. When used to mold a layer onto an existingstructure, such as a ball core, the mold includes a number of supportpins disposed throughout the mold sections. The support pins areconfigured to be retractable, moving into and out of the cavityperpendicular to the spherical cavity surface. The support pins maintainthe position of the core while the molten material flows through thegates into the cavity between the core and the mold sections. The molditself may be a cold mold or a heated mold

In contrast, compression molding of a ball cover or intermediate layertypically requires the initial step of making half shells by injectionmolding the layer material into an injection mold. The half shells thenare positioned in a compression mold around a ball core, whereupon heatand pressure are used to mold the half shells into a complete layer overthe core, with or without a chemical reaction such as crosslinking.Compression molding also can be used as a curing step after injectionmolding. In such a process, an outer layer of thermally curable materialis injection molded around a core in a cold mold. After the materialsolidifies, the ball is removed and placed into a mold, in which heatand pressure are applied to the ball to induce curing in the outerlayer.

Of the various cover molding processes, injection molding is mostpreferred, due to the efficiencies gained by its use including a morerapid cycle time, cheaper operating costs and an improved ability toproduce thinner layers around the core and closely control any thicknessvariation. This latter advantage is becoming more important with thedevelopments of multi-layered balls with two or more intermediate layersbetween the core and cover thus requiring thinner layer formation.

Like golf ball cores, golf ball covers and/or intermediate layers aresometimes made from rubber. Earlier balls almost exclusively had coversmade from naturally occurring balata rubber. Many players still favorthis cover material as its softness allows them to achieve spin ratessufficient to allow more precise control of ball direction and distance,particularly on shorter approach shots. However one deficiency of balatais the ease with which it is cut or sheared leading to low durability ofthe ball. Also, as with synthetic 1,4-polybutadiene rubber, balatarubber has relatively high viscosity at normal injection moldingtemperatures and thus is not easily adaptable to traditional thinlayer-forming injection molding techniques. Thus the current evolutionin golf balls technology favors the use of thermoplastic materials suchas ionomers or thermoplastic polyurethane in golf ball covers andintermediate layers, which materials are much more amenable to modernthin layer injection molding techniques.

However, in addition to the polybutadiene-based synthetic rubbers,another synthetic rubber available for use in golf balls, are theso-called “polyalkenamers”. These synthetic rubbers are unique in thatin addition to a liner polymeric component they also contain asignificant fraction of cyclic oligomer molecules, which in turn lowerstheir viscosity. Compounds of this class can be produced in accordancewith the teachings of U.S. Pat. Nos. 3,804,803, 3,974,092 and 4,950,826,the entire contents of all of which are herein incorporated byreference.

To date, this material has been utilized primarily in blends with otherpolymers. For instance, U.S. Pat. No. 4,183,876 describes compositionscomprising 15-95 parts by weight crystalline polyolefin resin andcorrespondingly 85-5 parts by weight cross-linked polyalkenamer rubberper 100 total parts by weight of resin and rubber. The resultingmoldable thermoplastic compositions were said to exhibit improvedstrength and greater toughness and impact resistance than similarcompositions containing substantially uncross-linked rubber. U.S. Pat.No. 4,840,993 describes a polyamide molding compound consisting of amixture of 60 to 98% by weight of (A) a polyamide and (B) 2 to 40% byweight of a polyalkenamer, wherein the mixture is treated at elevatedtemperatures with 0.05 to 5% by weight of the sum of components (A) and(B) of an organic radical former. No mention was made of the use of suchcompositions in balls including golf balls.

However, there a number of applications of polyalkenamer blends in gameballs of various kinds. For example, U.S. Pat. No. 5,460,367 describes apressureless tennis ball comprising a blend of trans-polyoctenamerrubber and natural rubber or other synthetic rubbers, e.g.cis-1,4-polybutadiene, trans-polybutadiene, polyisoprene,styrene-butadiene rubber, ethylene-propylene rubber or anethylene-propylene-diene rubber (EPDM).

Also, U.S. Pat. No. 4,792,141 describes a golf ball comprising a coreand a cover wherein the cover is formed from a composition comprisingabout 97 to about 60 parts balata and about 3 to about 40 parts byweight polyoctenylene rubber based on 100 parts by weight polymer in thecomposition. This patent also discloses that using more than about 40parts by weight of polyoctenylene based on 100 parts by weight polymerin the composition has been found to produce deleterious effects.

However, it would be highly advantageous to have an injection moldablerubber composition with the soft feel of a rubber such as balata, but ofsufficiently low viscosity to allow the material to be injection molded.It would also be highly advantageous if the properties of such a rubbercomposition could be tailored by similar formulation chemistry to thatwhich has evolved through the use of crosslinked filled polybutadienecompositions used in core construction. In particular, it would beadvantageous to have a composition that exhibits both superior toughness(e.g., durability) and high hardness. It would also be highlyadvantageous if such a composition could be used in a process to make agolf ball which process would include primarily injection molding tofabricate a core, outer cover and/or intermediate layer. It would alsobe highly advantageous if such a fabrication process would also allowformation of thin outer cover and/or intermediate layers, while alsoproviding facile control not only of layer thickness and thicknessuniformity, but while also allowing ease in variation of the resultingball properties.

The present disclosure provides a golf ball comprising an injectionmoldable polyalkenamer rubber composition for use in a core,intermediate layers and/or outer cover layer of a golf ball. The presentdisclosure also provides a golf ball comprising apolyalkenamer/polyamide rubber composition for use in a core,intermediate layers and/or outer cover layer of a golf ball. Theproperties of the composition may be easily tailored for the particulargolf ball component to be made by variation in the curative packageemployed and/or the molding conditions.

The present disclosure also provides processes for preparing a golf ballby injection molding one or more of the core, intermediate layers and/orouter cover layer of a golf ball. In one embodiment, the processutilizes a composition comprising a polyalkenamer rubber having asufficiently low viscosity at and below normal peroxide decompositiontemperatures to allow the material to be injection molded to form acore, intermediate and/or cover layer. In another embodiment, theprocess utilizes a composition comprising at least one polyalkenamerrubber having a sufficiently low viscosity to allow the material to beinjection molded to form a core, intermediate and/or cover layer, and atleast one polyamide.

SUMMARY

Disclosed herein are golf balls prepared from polyalkenamer/polyamidecompositions, methods for making such golf balls andpolyalkenamer/polyamide compositions. Also disclosed herein are golfballs prepared from polyalkenamer rubber compositions, and methods formaking such compositions.

According to one embodiment, there is disclosed a golf ball comprising:

(a) a core comprising a center;

(b) an outer cover layer; and

(c) one or more intermediate layers;

wherein at least one of the core, the outer cover layer, or theintermediate layer comprises a composition that includes at least onepolyalkenamer and at least one polyamide.

According to another embodiment, there is disclosed a golf ballcomprising:

(a) a core; and

(b) an outer cover layer;

wherein at least one of the core or the outer cover layer comprises acomposition that includes at least one polyalkenamer and at least onepolyamide.

In a further embodiment, there is disclosed a three piece golf ballcomprising:

(a) a core comprising a center;

(b) an outer cover layer comprising a thermoplastic elastomer, athermoset polyurethane, a thermoplastic polyurethane, a unimodalionomer, a bimodal ionomer, a modified unimodal ionomer, a modifiedbimodal ionomer; or any and all combinations or mixtures thereof; and

(c) an intermediate layer comprising an injection moldable compositioncomprising at least one polyalkenamer and at least about 10 weightpercent of at least one polyamide, based on the total polymer amount ofthe intermediate layer.

Another embodiment disclosed herein is a four piece golf ballcomprising:

(a) a core comprising a center;

(b) an outer cover layer comprising a thermoplastic elastomer, athermoset polyurethane, a thermoplastic polyurethane, a unimodalionomer, a bimodal ionomer, a modified unimodal ionomer, a modifiedbimodal ionomer; or any and all combinations or mixtures thereof;

(c) an inner intermediate layer comprising a thermoplastic elastomer, aunimodal ionomer, a bimodal ionomer, a modified unimodal ionomer, amodified bimodal ionomer; or any and all combinations or mixturesthereof; and

(d) an outer intermediate layer comprising an injection moldablecomposition comprising at least one polyalkenamer and at least about 10weight percent of at least one polyamide, based on the total polymeramount of the intermediate layer.

Also disclosed herein is a polymer composition that includes at leastone polyalkenamer and at least one thermoplastic copolyamide elastomer.

In one embodiment, a polymer composition may be prepared by forming ablend comprising at least one polyalkenamer rubber and at least onethermoplastic copolyamide elastomer.

A further aspect of the present disclosure concerns a method for makinga golf ball comprising a core, one or more intermediate layers and anouter cover layer, wherein the method comprises:

forming a blend comprising at least one polyalkenamer rubber and atleast one polyamide; and

injection molding the blend into a spherical mold to form theintermediate or outer cover layer.

According to a further embodiment, disclosed herein is a golf ballhaving:

-   -   a. a core comprising a center;    -   b. an outer cover layer; and    -   c. an intermediate layer comprising an injection moldable        polyalkenamer rubber composition, the injection moldable        polyalkenamer rubber composition further comprising:        -   i. at least one cross-linking agent selected from the group            consisting of sulfur compounds, peroxides, azides,            maleimides e-beam radiation, gamma—radiation, and all            combinations thereof; or        -   ii. at least one co-cross-linking agent comprising a zinc or            magnesium salts of an unsaturated fatty acid having from 3            to 8 carbon atoms, or        -   iii. at least one peptizer; or        -   iv. at least one accelerator; or        -   v. at least one filler; or        -   vi. any and all combinations of i, ii, iii, iv, and v.

Also disclosed herein is a method for making a golf ball comprising acore, one or more intermediate layers and an outer cover layer, whereinsaid method comprises the steps of;

1. forming a blend comprising a polyalkenamer rubber and one or moreadditional components selected from the group consisting of;

a. at least one cross-linking agent selected from the group consistingof sulfur compounds, peroxides, azides, maleimides e-beam radiation,gamma-radiation, and all combinations thereof;

b. at least one co-cross-linking agent comprising a zinc or magnesiumsalts of an unsaturated fatty acid having from 3 to 8 carbon atoms, and

c. any and all combinations of a and b; and

2. injection molding the blend of step 1 into a spherical mold to formthe intermediate or outer cover layer wherein said mold is maintained ata temperature such that the desired amount of crosslinking of thepolyalkenamer rubber occurs.

The foregoing and other features and advantages will become moreapparent from the following detailed description, which proceeds withreference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the drawing in FIG. 1 there is illustrated a golf ball, 1,which comprises a solid center or core, 2, formed as a solid body of theherein described formulation and in the shape of the sphere, anintermediate layer, 3, disposed on the spherical core and an outer coverlayer, 4.

Referring to the drawing in FIG. 2 there is illustrated a golf ball, 1,which comprises a solid center or core, 2, formed as a solid body of theherein described formulation and in the shape of the sphere, an innerintermediate layer, 3, disposed on the spherical core, an outerintermediate layer, 4, disposed on the inner intermediate layer, 3, andan outer cover layer, 5.

DETAILED DESCRIPTION

For ease of understanding, the following terms used herein are describedbelow in more detail:

The term “(meth)acrylic acid copolymers” refers to copolymers ofmethacrylic acid and/or acrylic acid.

The term “(meth)acrylate” refers to an ester of methacrylic acid and/oracrylic acid.

The term “partially neutralized” refers to an ionomer with a degree ofneutralization of less than 100 percent.

The term “hydrocarbyl” includes any aliphatic, cycloaliphatic, aromatic,aryl substituted aliphatic, aryl substituted cycloaliphatic, aliphaticsubstituted aromatic, or cycloaliphatic substituted aromatic groups. Thealiphatic or cycloaliphatic groups are preferably saturated. Likewise,the term “hydrocarbyloxy” means a hydrocarbyl group having an oxygenlinkage between it and the carbon atom to which it is attached.

The term “core” refers to the elastic center of a golf ball, which mayhave a unitary construction. Alternatively the core itself may have alayered construction having a spherical “center” and additional “corelayers”, which such layers usually being made of the same material asthe core center.

The term “cover” is meant to include any layer of a golf ball, whichsurrounds the core. Thus a golf ball cover may include both theoutermost layer and also any intermediate layers, which are disposedbetween the golf ball center and outer cover layer. The term cover asused herein is used interchangeably with the term “cover layer”.

The term “outer cover layer” refers to the outermost cover layer of thegolf ball; this is the layer that is directly in contact with paintand/or ink on the surface of the golf ball and on which the dimplepattern is placed. If, in addition to the core, a golf ball comprisestwo or more cover layers, only the outermost layer is designated theouter cover layer, and the remaining layers are commonly designatedintermediate layers as herein defined. The term outer cover layer asused herein is used interchangeably with the term “outer cover”.

The term “intermediate layer” may be used interchangeably herein withthe terms “mantle layer” or “inner cover layer” or “inner cover” and isintended to mean any layer(s) in a golf ball disposed between the coreand the outer cover layer. The intermediate layer may be in the shape ofa hollow, thin-skinned sphere that may or may not include inward oroutward protrusions (e.g., the intermediate layer may be ofsubstantially the same thickness around its entire curvature).

In the case of a ball with two intermediate layers, the term “innerintermediate layer” may be used interchangeably herein with the terms“inner mantle” or “inner mantle layer” and refers to the intermediatelayer of the ball which is disposed nearest to the core.

Again, in the case of a ball with two intermediate layers, the term“outer intermediate layer” may be used interchangeably herein with theterms “outer mantle” or “outer mantle layer” and refers to theintermediate layer of the ball which is disposed nearest to the outercover layer.

The term “bimodal polymer” refers to a polymer comprising two mainfractions and more specifically to the form of the polymers molecularweight distribution curve, i.e., the appearance of the graph of thepolymer weight fraction as function of its molecular weight. When themolecular weight distribution curves from these fractions aresuperimposed into the molecular weight distribution curve for the totalresulting polymer product, that curve will show two maxima or at leastbe distinctly broadened in comparison with the curves for the individualfractions. Such a polymer product is called bimodal. It is to be notedhere that also the chemical compositions of the two fractions may bedifferent.

Similarly the term “unimodal polymer” refers to a polymer comprising onemain fraction and more specifically to the form of the polymer'smolecular weight distribution curve, i.e., the molecular weightdistribution curve for the total polymer product shows only a singlemaximum.

The term “polyalkenamer” is used interchangeably herein with the term“polyalkenamer rubber” and means a rubbery polymer of one or morecycloalkenes having from 5-20, preferably 5-15, most preferably 5-12ring carbon atoms. The polyalkenamers may be prepared by ring openingmetathesis polymerization of one or more cycloalkenes in the presence oforganometallic catalysts as described in U.S. Pat. Nos. 3,492,245, and3,804,803, the entire contents of both of which are herein incorporatedby reference.

Examples of suitable polyalkenamer rubbers are polypentenamer rubber,polyheptenamer rubber, polyoctenamer rubber, polydecenamer rubber andpolydodecenamer rubber. For further details concerning polyalkenamerrubber, see Rubber Chem. & Tech., Vol. 47, page 511-596, 1974, which isincorporated herein by reference. Polyoctenamer rubbers are commerciallyavailable from Huls AG of Marl, Germany, and through its distributor inthe U.S., Creanova Inc. of Somerset, N.J., and sold under the trademarkVESTENAMER®. Two grades of the VESTENAMER® trans-polyoctenamer arecommercially available: VESTENAMER 8012 designates a material having atrans-content of approximately 80% (and a cis-content of 20%) with amelting point of approximately 54° C.; and VESTENAMER 6213 designates amaterial having a trans-content of approximately 60% (cis-content of40%) with a melting point of approximately 30° C. Both of these polymershave a double bond at every eighth carbon atom in the ring.

The polyalkenamer rubbers used in the present disclosure exhibitexcellent melt processability above their sharp melting temperatures andexhibit high miscibility with various rubber additives as a majorcomponent without deterioration of crystallinity which in turnfacilitates injection molding. Thus, unlike synthetic rubbers typicallyused in golf ball preparation, injection molded parts ofpolyalkenamer-based compounds can be prepared which, in addition, canalso be partially or fully crosslinked at elevated temperature. Thecrosslinked polyoctenamer compounds are highly elastic, and theirmechanical and physical properties can be easily modified by adjustingthe formulation.

As used herein, the term “injection moldable” as applied to thepolyalkenamer rubber or polyalkenamer/polyamide compositions used asdescribed herein refers to a material amenable to use in injectionmolding apparatus designed for use with typical thermoplastic resins. Inone example, the term injection moldable composition as applied to theuncrosslinked polyalkenamer rubbers used in the present disclosure meanscompositions having a viscosity using a Dynamic Mechanical Analyzer(DMA) and ASTM D4440 at 200° C. of less than about 5,000 Pa-sec,preferably less than about 3,000 Pa-sec, more preferably less than about2,000 Pa-sec and even more preferably less than about 1,000 Pa-sec. anda storage modulus (G′) at 1 Hz measured using a Dynamic MechanicalAnalyzer (DMA) and ASTM D4065, and ASTM D4440, at 25° C., and 1 Hz ofgreater than about 1×10⁷ dyn/cm², preferably greater than about 1.5×10⁷dyn/cm², more preferably greater than about 1×10⁸ dyn/cm², and mostpreferably greater than about 2×10⁸ dyn/cm².

The term “polyamide” includes both homopolyamides and copolyamides.

The above term descriptions are provided solely to aid the reader, andshould not be construed to have a scope less than that understood by aperson of ordinary skill in the art or as limiting the scope of theappended claims.

The singular terms “a,” “an,” and “the” include plural referents unlesscontext clearly indicates otherwise. The word “comprises” indicates“includes.” It is further to be understood that all molecular weight ormolecular mass values given for compounds are approximate, and areprovided for description. The materials, methods, and examples areillustrative only and not intended to be limiting. Unless otherwiseindicated, description of components in chemical nomenclature refers tothe components at the time of addition to any combination specified inthe description, but does not necessarily preclude chemical interactionsamong the components of a mixture once mixed.

Any numerical values recited herein include all values from the lowervalue to the upper value in increments of one unit provided that thereis a separation of at least 2 units between any lower value and anyhigher value. As an example, if it is stated that the amount of acomponent or a value of a process variable is from 1 to 90, preferablyfrom 20 to 80, more preferably from 30 to 70, it is intended that valuessuch as 15 to 85, 22 to 68, 43 to 51, 30 to 32 etc., are expresslyenumerated in this specification. For values, which have less than oneunit difference, one unit is considered to be 0.1, 0.01, 0.001, or0.0001 as appropriate. Thus all possible combinations of numericalvalues between the lowest value and the highest value enumerated hereinare said to be expressly stated in this application.

The polyalkenamer/polyamide composition surprisingly exhibits superiorcharacteristics over a broad spectrum of properties that relate to theeffectiveness of a composition for use in a golf ball. For example, thecomposition exhibits superior impact durability and Coefficient ofRestitution (COR) in a pre-determined hardness range (e.g., a hardnessShore D of from about 30 to about 85, preferably from about 40 to about80, and more preferably from about 40 to about 75). More particularly,the compositions disclosed herein exhibit excellent hardness adjustmentwithout significantly compromising COR or processability. In otherwords, the hardness (rigidness) of polyamide compositions typically istoo great for use as a major or primary ingredient in a golf ballcomposition, but it has been discovered that by adding a polyalkenamerto the polyamide composition the hardness can be lowered withoutsignificantly compromising COR or processability.

A surprising aspect of the disclosed compositions is that combining thepolyamide with the polyalkenamer does not decrease the CORsignificantly. Typically, it would have been expected that blendingpolyamide with other polymeric component(s) would significantly decreasethe COR.

Unlike synthetic rubbers typically used in golf ball preparation,injection molded parts of polyalkenamer/polyamide-based compositions canbe prepared which, in addition, can also be partially, fullycrosslinked, or annealed at elevated temperature. The crosslinked orthermally treated polyalkenamer/polyamide compositions are highlyelastic, and their mechanical and physical properties can be easilymodified by adjusting the formulation.

The presently disclosed compositions can be used in forming golf ballsof any desired size. “The Rules of Golf” by the USGA dictate that thesize of a competition golf ball must be at least 1.680 inches indiameter; however, golf balls of any size can be used for leisure golfplay. The preferred diameter of the golf balls is from about 1.670inches to about 1.800 inches or about 1.680 inches to about 1.800inches. The more preferred diameter is from about 1.680 inches to about1.760 inches. A diameter of from about 1.680 inches to about 1.740inches is most preferred; however diameters anywhere in the range offrom 1.70 to about 2.0 inches can be used. Oversize golf balls withdiameters above about 1.760 inches to as big as 2.75 inches are alsowithin the scope of the disclosure.

The present disclosure relates to a golf ball comprising a core, a coverlayer and, optionally, one or more inner cover layers and where one ormore of the core, cover layer or inner cover layers comprises apolyalkenamer/polyamide rubber composition. In one preferred embodiment,a golf ball is disclosed in which the cover layer comprises thepolyalkenamer/polyamide rubber composition. In another preferredembodiment, a golf ball is disclosed in which at least one intermediatelayer comprises the polyalkenamer/polyamide rubber composition. Inanother preferred embodiment, a golf ball is disclosed in which the corecomprises the polyalkenamer/polyamide rubber composition.

The polyalkenamer/polyamide composition used to prepare the golf ballcontains from about 2 to about 90 wt %, preferably from about 5 to about80 wt %, more preferably from about 7 to 70 wt %, and even morepreferably from about 10 to 60 wt % (based on the final weight of theinjection moldable composition) of one or more polyalkenamer polymers,particularly polyalkenamers of a cycloalkene having from 5-20,preferably 5-15, and most preferably 5-12 ring carbon atoms. Thepolyalkenamers may be prepared by ring opening metathesis polymerizationof one or more cycloalkenes in the presence of organometallic catalystsas described in U.S. Pat. Nos. 3,492,245, and 3,804,803, the entirecontents of both of which are herein incorporated by reference.

The polyalkenamer/polyamide composition used to prepare the golf ballalso contains from about 10 to about 98 wt %, preferably from about 20to about 95 wt %, more preferably from about 30 to 93 wt %, and evenmore preferably from about 40 to 90 wt % (based on the final weight ofthe injection moldable composition) of one or more polyamide polymers.

According to certain embodiments, the polyalkenamer/polyamidecomposition contains at least about 60 wt %, preferably at least about70 wt %, and more preferably at least about 80 wt % of at least onepolyamide, based on the total polymer amount of the layer(s) or corethat is made from the polyalkenamer/polyamide composition. In furtherembodiments, the polyamide ingredient of the polyalkenamer/polyamidecomposition is the major ingredient of the material used to form atleast one component (e.g., the core or inner cover layer) of the golfball. As used herein “major ingredient” means that the polyamide ispresent in an amount of at least about 50 wt %, based on the totalweight of all the ingredients in the material.

In another embodiment disclosed herein, there is a golf ball comprisinga core, a cover layer and, optionally, one or more inner cover layersand where one or more of the core, cover layer or inner cover layerscomprises an injection moldable rubber composition. In one preferredembodiment, a golf ball is disclosed in which the cover layer comprisesthe injection moldable rubber composition. In another preferredembodiment, a golf ball is disclosed in which at least one intermediatelayer comprises the injection moldable rubber composition. In anotherpreferred embodiment, a golf ball is disclosed in which the corecomprises the injection moldable rubber composition.

In a further embodiment, the injection moldable composition used toprepare the golf ball contains from about 1 to 100 wt %, preferably fromabout 20 to 100 wt %, more preferably from about 40 to 100 wt % or 45 to100 wt %, and even more preferably from about 60 to 100 wt % or 75 to100 wt % (based on the final weight of the injection moldablecomposition) of one or more polyalkenamer polymers of a cycloalkenehaving from 5-20, preferably 5-15, and most preferably 5-12 ring carbonatoms.

Illustrative polyamides for use in the polyalkenamer/polyamidecompositions include those obtained by: (1) polycondensation of (a) adicarboxylic acid, such as oxalic acid, adipic acid, sebacic acid,terephthalic acid, isophthalic acid, or 1,4-cyclohexanedicarboxylicacid, with (b) a diamine, such as ethylenediamine,tetramethylenediamine, pentamethylenediamine, hexamethylenediamine,decamethylenediamine, 1,4-cyclohexyldiamine or m-xylylenediamine; (2) aring-opening polymerization of cyclic lactam, such as ε-caprolactam orω-laurolactam; (3) polycondensation of an aminocarboxylic acid, such as6-aminocaproic acid, 9-aminononanoic acid, 11-aminoundecanoic acid or12-aminododecanoic acid; (4) copolymerization of a cyclic lactam with adicarboxylic acid and a diamine; or any combination of (1)-(4). Incertain examples, the dicarboxylic acid may be an aromatic dicarboxylicacid or a cycloaliphatic dicarboxylic acid. In certain examples, thediamine may be an aromatic diamine or a cycloaliphatic diamine. Specificexamples of suitable polyamides include polyamide 6; polyamide 11;polyamide 12; polyamide 4,6; polyamide 6,6; polyamide 6,9; polyamide6,10; polyamide 6,12; polyamide MXD6; PA12,CX; PA12, IT; PPA; PA6, IT;and PA6/PPE.

The polyamide may be any homopolyamide or copolyamide. One example of agroup of suitable polyamides are thermoplastic polyamide elastomers.Thermoplastic polyamide elastomers typically are copolymers of apolyamide and polyester or polyether. For example, the thermoplasticpolyamide elastomer can contain a polyamide (Nylon 6, Nylon 66, Nylon11, Nylon 12 and the like) as a hard segment and a polyether orpolyester as a soft segment. In one specific example, the thermoplasticpolyamides are amorphous copolyamides based on polyamide (PA 12).

One class of copolyamide elastomers are polyether amide elastomers.Illustrative examples of polyether amide elastomers are those thatresult from the copolycondensation of polyamide blocks having reactivechain ends with polyether blocks having reactive chain ends, including:

(1) polyamide blocks of diamine chain ends with polyoxyalkylenesequences of dicarboxylic chains;

(2) polyamide blocks of dicarboxylic chain ends with polyoxyalkylenesequences of diamine chain ends obtained by cyanoethylation andhydrogenation of polyoxyalkylene alpha-omega dihydroxylated aliphaticsequences known as polyether diols; and

(3) polyamide blocks of dicarboxylic chain ends with polyether diols,the products obtained, in this particular case, beingpolyetheresteramides.

More specifically, the polyamide elastomer can be prepared bypolycondensation of the components (i) a diamine and a dicarboxylate,lactames or an amino dicarboxylic acid (PA component), (ii) apolyoxyalkylene glycol such as polyoxyethylene glycol, polyoxy propyleneglycol (PG component) and (iii) a dicarboxylic acid.

The polyamide blocks of dicarboxylic chain ends come, for example, fromthe condensation of alpha-omega aminocarboxylic acids of lactam or ofcarboxylic diacids and diamines in the presence of a carboxylic diacidwhich limits the chain length. The molecular weight of the polyamidesequences is preferably between about 300 and 15,000, and morepreferably between about 600 and 5,000. The molecular weight of thepolyether sequences is preferably between about 100 and 6,000, and morepreferably between about 200 and 3,000.

The amide block polyethers may also comprise randomly distributed units.These polymers may be prepared by the simultaneous reaction of polyetherand precursor of polyamide blocks. For example, the polyether diol mayreact with a lactam (or alpha-omega amino acid) and a diacid whichlimits the chain in the presence of water. A polymer is obtained thathas primarily polyether blocks and/or polyamide blocks of very variablelength, but also the various reactive groups that have reacted in arandom manner and which are distributed statistically along the polymerchain.

Suitable amide block polyethers include those as disclosed in U.S. Pat.Nos. 4,331,786; 4,115,475; 4,195,015; 4,839,441; 4,864,014; 4,230,848and 4,332,920.

The polyether may be, for example, a polyethylene glycol (PEG), apolypropylene glycol (PPG), or a polytetramethylene glycol (PTMG), alsodesignated as polytetrahydrofurane (PTHF). The polyether blocks may bealong the polymer chain in the form of diols or diamines. However, forreasons of simplification, they are designated PEG blocks, or PPGblocks, or also PTMG blocks.

The polyether block comprises different units such as units which derivefrom ethylene glycol, propylene glycol, or tetramethylene glycol.

The amide block polyether comprises at least one type of polyamide blockand one type of polyether block. Mixing of two or more polymers withpolyamide blocks and polyether blocks may also be used. The amide blockpolyether also can comprise any amide structure made from the methoddescribed on the above.

Preferably, the amide block polyether is such that it represents themajor component in weight, i.e., that the amount of polyamide which isunder the block configuration and that which is eventually distributedstatistically in the chain represents 50 weight percent or more of theamide block polyether. Advantageously, the amount of polyamide and theamount of polyether is in a ratio (polyamide/polyether) of 1/1 to 3/1.

One type of polyetherester elastomer is the family of Pebax, which areavailable from Elf-Atochem Company. Preferably, the choice can be madefrom among Pebax 2533, 3533, 4033, 1205, 7033 and 7233. Blends orcombinations of Pebax 2533, 3533, 4033, 1205, 7033 and 7233 can also beprepared, as well. Pebax 2533 has a hardness of about 25 shore D(according to ASTM D-2240), a Flexural Modulus of 2.1 kpsi (according toASTM D-790), and a Bayshore resilience of about 62% (according to ASTMD-2632). Pebax 3533 has a hardness of about 35 shore D (according toASTM D-2240), a Flexural Modulus of 2.8 kpsi (according to ASTM D-790),and a Bayshore resilience of about 59% (according to ASTM D-2632). Pebax7033 has a hardness of about 69 shore D (according to ASTM D-2240) and aFlexural Modulus of 67 kpsi (according to ASTM D-790). Pebax 7333 has ahardness of about 72 shore D (according to ASTM D-2240) and a FlexuralModulus of 107 kpsi (according to ASTM D-790).

Some examples of suitable polyamides for use in thepolyalkenamer/polyamide compositions include those commerciallyavailable under the tradenames PEBAX, CRISTAMID and RILSAN marketed byAtofina Chemicals of Philadelphia, Pa., GRIVORY and GRILAMID marketed byEMS Chemie of Sumter, S.C., TROGAMID and VESTAMID available fromDegussa, and ZYTEL marketed by E.I. DuPont de Nemours & Co., ofWilmington, Del.

The polyalkenamer rubber preferably contains from about 50 to about 99,preferably from about 60 to about 99, more preferably from about 65 toabout 99, even more preferably from about 70 to about 90 percent of itsdouble bonds in the trans-configuration. The preferred form of thepolyalkenamer has a trans content of approximately 80%, however,compounds having other ratios of the cis- and trans-isomeric forms ofthe polyalkenamer can also be obtained by blending available productsfor use in making the composition.

The polyalkenamer rubber has a molecular weight (as measured by GPC)from about 10,000 to about 300,000, preferably from about 20,000 toabout 250,000, more preferably from about 30,000 to about 200,000, evenmore preferably from about 50,000 to about 150,000.

The polyalkenamer rubber has a degree of crystallization (as measured byDSC secondary fusion) from about 5 to about 70, preferably from about 6to about 50, more preferably from about from 6.5 to about 50%, even morepreferably from about from 7 to about 45%,

More preferably, the polyalkenamer rubber is a polymer prepared bypolymerization of cyclooctene to form a trans-polyoctenamer rubber as amixture of linear and cyclic macromolecules.

Prior to its use in golf balls, the polyalkenamer rubber or thepolyalkenamer/polyamide composition may be further formulated with oneor more of the following blend components:

A. Cross-Linking Agents

Any crosslinking or curing system typically used for rubber crosslinkingmay be used to crosslink the polyalkenamer rubber and/or polyamide.Satisfactory crosslinking systems are based on sulfur-, peroxide-,azide-, maleimide- or resin-vulcanization agents, which may be used inconjunction with a vulcanization accelerator. Examples of satisfactorycrosslinking system components are zinc oxide, sulfur, organic peroxide,azo compounds, magnesium oxide, benzothiazole sulfenamide accelerator,benzothiazyl disulfide, phenolic curing resin, m-phenylenebis-maleimide, thiuram disulfide and dipentamethylene-thiuramhexasulfide.

More preferable cross-linking agents include peroxides, sulfurcompounds, as well as mixtures of these. Non-limiting examples ofsuitable cross-linking agents include primary, secondary, or tertiaryaliphatic or aromatic organic peroxides. Peroxides containing more thanone peroxy group can be used, such as2,5-dimethyl-2,5-di(tert-butylperoxy)hexane and 1,4-di-(2-tert-butylperoxyisopropyl)benzene. Both symmetrical and asymmetrical peroxides canbe used, for example, tert-butyl perbenzoate and tert-butyl cumylperoxide. Peroxides incorporating carboxyl groups also are suitable. Thedecomposition of peroxides used as cross-linking agents in the disclosedcompositions can be brought about by applying thermal energy, shear,irradiation, reaction with other chemicals, or any combination of these.Both homolytically and heterolytically decomposed peroxide can be used.Non-limiting examples of suitable peroxides include: diacetyl peroxide;di-tert-butyl peroxide; dibenzoyl peroxide; dicumyl peroxide;2,5-dimethyl-2,5-di(benzoylperoxy)hexane;1,4-bis-(t-butylperoxyisopropyl)benzene; t-butylperoxybenzoate;2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3, such as Trigonox 145-45B,marketed by Akrochem Corp. of Akron, Ohio; 1,1-bis(t-butylperoxy)-3,3,5tri-methylcyclohexane, such as Varox 231-XL, marketed by R.T. VanderbiltCo., Inc. of Norwalk, Conn.; and di-(2,4-dichlorobenzoyl)peroxide.

The cross-linking agents can be blended in total amounts of about 0.01part to about 5 parts, more preferably about 0.05 part to about 4 parts,and most preferably about 0.1 part to about 2 parts, by weight of thecross-linking agents per 100 parts by weight of thepolyalkenamer/polyamide composition. The cross-linking agent(s) may bemixed into or with the polyalkenamer/polyamide blend, or thecross-linking agent(s) may be pre-mixed with the polyalkenamer orpolyamide component prior to the compounding of polyalkenamer orpolyamide components.

In a further embodiment, the cross-linking agents can be blended intotal amounts of about 0.05 part to about 5 parts, more preferably about0.2 part to about 3 parts, and most preferably about 0.2 part to about 2parts, by weight of the cross-linking agents per 100 parts by weight ofthe polyalkenamer rubber.

Each peroxide cross-linking agent has a characteristic decompositiontemperature at which 50% of the cross-linking agent has decomposed whensubjected to that temperature for a specified time period (t_(1/2)). Forexample, 1,1-bis-(t-butylperoxy)-3,3,5-tri-methylcyclohexane att_(1/2)=0.1 hour has a decomposition temperature of 138° C. and2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3 at t_(1/2)=0.1 hour has adecomposition temperature of 182° C. Two or more cross-linking agentshaving different characteristic decomposition temperatures at the samet_(1/2) may be blended in the composition. For example, where at leastone cross-linking agent has a first characteristic decompositiontemperature less than 150° C., and at least one cross-linking agent hasa second characteristic decomposition temperature greater than 150° C.,the composition weight ratio of the at least one cross-linking agenthaving the first characteristic decomposition temperature to the atleast one cross-linking agent having the second characteristicdecomposition temperature can range from 5:95 to 95:5, or morepreferably from 10:90 to 50:50.

Besides the use of chemical cross-linking agents, exposure of thepolyalkenamer rubber/polyamide composition, or polyalkenamer rubbercomposition, to radiation also can serve as a cross-linking agent.Radiation can be applied to the polyalkenamer rubber/polyamide mixtureby any known method, including using microwave or gamma radiation, or anelectron beam device. Additives may also be used to improveradiation-induced crosslinking of the polyalkenamer rubber/polyamidecomposition or polyalkenamer rubber composition.

B. Co-Cross-Linking Agent

The polyalkenamer rubber/polyamide composition, or polyalkenamer rubbercomposition, may also be blended with a co-cross-linking agent, whichmay be a metal salt of an unsaturated carboxylic acid. Examples of theseinclude zinc and magnesium salts of unsaturated fatty acids having 3 to8 carbon atoms, such as acrylic acid, methacrylic acid, maleic acid, andfumaric acid, palmitic acid with the zinc salts of acrylic andmethacrylic acid being most preferred. The unsaturated carboxylic acidmetal salt can be blended in the polyalkenamer rubber/polyamidecomposition, or polyalkenamer rubber composition, either as a preformedmetal salt, or by introducing an α,β-unsaturated carboxylic acid and ametal oxide or hydroxide into the polyalkenamer rubber/polyamidecomposition or polyalkenamer rubber composition, and allowing them toreact to form the metal salt. The unsaturated carboxylic acid metal saltcan be blended in any desired amount, but preferably in amounts of about1 part to about 100 parts by weight of the unsaturated carboxylic acidper 100 parts by weight of the polyalkenamer rubber/polyamidecomposition, or polyalkenamer rubber composition.

C. Peptizer

The polyalkenamer rubber/polyamide compositions, or polyalkenamer rubbercomposition, may also incorporate one or more of the so-called“peptizers”.

The peptizer preferably comprises an organic sulfur compound and/or itsmetal or non-metal salt. Examples of such organic sulfur compoundsinclude thiophenols, such as pentachlorothiophenol,4-butyl-o-thiocresol, 4 t-butyl-p-thiocresol, and 2-benzamidothiophenol;thiocarboxylic acids, such as thiobenzoic acid; 4,4′ dithiodimorpholine; and, sulfides, such as dixylyl disulfide, dibenzoyldisulfide; dibenzothiazyl disulfide; di(pentachlorophenyl)disulfide;dibenzamido diphenyldisulfide (DBDD), and alkylated phenol sulfides,such as VULTAC marketed by Atofina Chemicals, Inc. of Philadelphia, Pa.Preferred organic sulfur compounds include pentachlorothiophenol, anddibenzamido diphenyldisulfide.

Examples of the metal salt of an organic sulfur compound include sodium,potassium, lithium, magnesium calcium, barium, cesium and zinc salts ofthe above-mentioned thiophenols and thiocarboxylic acids, with the zincsalt of pentachlorothiophenol being most preferred.

Examples of the non-metal salt of an organic sulfur compound includeammonium salts of the above-mentioned thiophenols and thiocarboxylicacids wherein the ammonium cation has the general formula [NR¹R²R³R⁴]⁺where R¹, R², R³ and R⁴ are selected from the group consisting ofhydrogen, a C₁-C₂₀ aliphatic, cycloaliphatic or aromatic moiety, and anyand all combinations thereof, with the most preferred being the NH₄⁺-salt of pentachlorothiophenol.

For example, ammonium pentachlorothiophenol can be made frompentachlorothiophenol (purchased from Dannier Chemicals), which issuspended in para-xylene (100 g in 250 ml). The suspension is stirred,warmed to 35° C. To this suspension, 1 molar equivalent of concentratedaqueous ammonium hydroxide is added and allowed to react for 5 minuteswith stirring. Upon addition of ammonium hydroxide, the suspensionimmediately changes color from a green grey to a yellow orange color. Oncooling the resulting suspended ammonium pentachlorothiophenol is thenisolated by filtration, washed with xylene and dried under vacuum atroom temperature for 72 hours. Zinc pentachlorothiophenol may bepurchased from Dannier Chemicals.

The peptizer, if employed in the golf balls, is present in an amount offrom about 0.01 to about 10, preferably of from about 0.05 to about 7,more preferably of from about 0.1 to about 5 parts by weight per 100parts by weight of the polyalkenamer rubber/polyamide component.

D. Accelerators

The polyalkenamer rubber/polyamide composition, or polyalkenamer rubbercomposition, can also comprise one or more accelerators of one or moreclasses. Accelerators are added to an unsaturated polymer to increasethe vulcanization rate and/or decrease the vulcanization temperature.Accelerators can be of any class known for rubber processing includingmercapto-, sulfenamide-, thiuram, dithiocarbamate,dithiocarbamyl-sulfenamide, xanthate, guanidine, amine, thiourea, anddithiophosphate accelerators. Specific commercial accelerators include2-mercaptobenzothiazole and its metal or non-metal salts, such asVulkacit Mercapto C, Mercapto MGC, Mercapto ZM-5, and ZM marketed byBayer AG of Leverkusen, Germany, Nocceler M, Nocceler MZ, and NoccelerM-60 marketed by Ouchisinko Chemical Industrial Company, Ltd. of Tokyo,Japan, and MBT and ZMBT marketed by Akrochem Corporation of Akron, Ohio.A more complete list of commercially available accelerators is given inThe Vanderbilt Rubber Handbook. 13^(th) Edition (1990, R.T. VanderbiltCo.), pp. 296-330, in Encyclopedia of Polymer Science and Technology,Vol. 12 (1970, John Wiley & Sons), pp. 258-259, and in Rubber TechnologyHandbook (1980, Hanser/Gardner Publications), pp. 234-236. Preferredaccelerators include 2-mercaptobenzothiazole (MBT) and its salts.

The polyalkenamer rubber/polyamide composition, or polyalkenamer rubbercomposition, can further incorporate from about 0.01 part to about 10parts by weight of the accelerator per 100 parts by weight of thepolyalkenamer rubber/polyamide composition. More preferably, the ballcomposition can further incorporate from about 0.02 part to about 5parts, and most preferably from about 0.03 part to about 1.5 parts, byweight of the accelerator per 100 parts by weight of the polyalkenamerrubber.

Additional Polymer Components

The polyalkenamer rubber/polyamide composition, or polyalkenamer rubbercomposition, used in the core, outer cover layer and/or one or moreintermediate layers golf ball may be further blended with additionalpolymers prior to molding. Also, any of the core, outer cover layerand/or one or more intermediate layers of the balls, if not containingthe polyalkenamer/polyamide composition (or polyalkenamer rubbercomposition), may comprise one or more of the following additionalpolymers.

Such additional polymers include synthetic and natural rubbers,thermoset polymers such as thermoset polyurethanes and thermosetpolyureas, as well as thermoplastic polymers including thermoplasticelastomers such as unimodal ethylene/carboxylic acid copolymers,unimodal ethylene/carboxylic acid/carboxylate terpolymers, bimodalethylene/carboxylic acid copolymers, bimodal ethylene/carboxylicacid/carboxylate terpolymers, unimodal ionomers, bimodal ionomers,modified unimodal ionomers, modified bimodal ionomers, thermoplasticpolyurethanes, thermoplastic polyureas, polyesters, copolyesters,polycarbonates, polyolefins, polyphenylene oxide, polyphenylene sulfide,diallyl phthalate polymer, polyimides, polyvinyl chloride,polyamide-ionomer, polyurethane-ionomer, polyvinyl alcohol, polyarylate,polyacrylate, polyphenylene ether, impact-modified polyphenylene ether,polystyrene, high impact polystyrene, acrylonitrile-butadiene-styrenecopolymer styrene-acrylonitrile (SAN),acrylonitrile-styrene-acrylonitrile, styrene-maleic anhydride (S/MA)polymer, styrenic copolymer, functionalized styrenic copolymer,functionalized styrenic terpolymer, styrenic terpolymer, cellulosepolymer, liquid crystal polymer (LCP), ethylene-propylene-dieneterpolymer (EPDM), ethylene-vinyl acetate copolymers (EVA),ethylene-propylene copolymer, ethylene vinyl acetate, polyurea, andpolysiloxane and any and all combinations thereof. One example isParaloid EXL 2691A which is a methacrylate-butadiene-styrene (MBS)impact modifier available from Rohm & Haas Co.

More particularly, the synthetic and natural rubber polymers may includethe traditional rubber components used in golf ball applicationsincluding, both natural and synthetic rubbers, such ascis-1,4-polybutadiene, trans-1,4-polybutadiene, 1,2-polybutadiene,cis-polyisoprene, trans-polyisoprene, polychloroprene, polybutylene,styrene-butadiene rubber, styrene-butadiene-styrene block copolymer andpartially and fully hydrogenated equivalents, styrene-isoprene-styreneblock copolymer and partially and fully hydrogenated equivalents,nitrile rubber, silicone rubber, and polyurethane, as well as mixturesof these. Polybutadiene rubbers, especially 1,4-polybutadiene rubberscontaining at least 40 mol %, and more preferably 80 to 100 mol % ofcis-1,4 bonds, are preferred because of their high rebound resilience,moldability, and high strength after vulcanization. The polybutadienecomponent may be synthesized by using rare earth-based catalysts,nickel-based catalysts, or cobalt-based catalysts, conventionally usedin this field. Polybutadiene obtained by using lanthanum rareearth-based catalysts usually employ a combination of a lanthanum rareearth (atomic number of 57 to 71)-compound, but particularly preferredis a neodymium compound.

The 1,4-polybutadiene rubbers have a molecular weight distribution(Mw/Mn) of from about 1.2 to about 4.0, preferably from about 1.7 toabout 3.7, even more preferably from about 2.0 to about 3.5, mostpreferably from about 2.2 to about 3.2. The polybutadiene rubbers have aMooney viscosity (ML₁₊₄ (100° C.)) of from about 20 to about 80,preferably from about 30 to about 70, even more preferably from about 30to about 60, most preferably from about 35 to about 50. The term “Mooneyviscosity” used herein refers in each case to an industrial index ofviscosity as measured with a Mooney viscometer, which is a type ofrotary plastometer (see JIS K6300). This value is represented by thesymbol ML₁₊₄ (100° C.), wherein “M” stands for Mooney viscosity, “L”stands for large rotor (L-type), “1+4” stands for a pre-heating time of1 minute and a rotor rotation time of 4 minutes, and “100° C.” indicatesthat measurement was carried out at a temperature of 100° C.

Examples of 1,2-polybutadienes having differing tacticity, all of whichare suitable as unsaturated polymers for use in the presently disclosedcompositions, are atactic 1,2-polybutadiene, isotactic1,2-polybutadiene, and syndiotactic 1,2-polybutadiene. Syndiotactic1,2-polybutadiene having crystallinity suitable for use as anunsaturated polymer in the presently disclosed compositions arepolymerized from a 1,2-addition of butadiene. The presently disclosedgolf balls may include syndiotactic 1,2-polybutadiene havingcrystallinity and greater than about 70% of 1,2-bonds, more preferablygreater than about 80% of 1,2-bonds, and most preferably greater thanabout 90% of 1,2-bonds. Also, the 1,2-polybutadiene may have a meanmolecular weight between about 10,000 and about 350,000, more preferablybetween about 50,000 and about 300,000, more preferably between about80,000 and about 200,000, and most preferably between about 10,000 andabout 150,000. Examples of suitable syndiotactic 1,2-polybutadieneshaving crystallinity suitable for use in golf balls are sold under thetrade names RB810, RB820, and RB830 by JSR Corporation of Tokyo, Japan.These have more than 90% of 1,2 bonds, a mean molecular weight ofapproximately 120,000, and crystallinity between about 15% and about30%.

Examples of olefinic thermoplastic elastomers includemetallocene-catalyzed polyolefins, ethylene-octene copolymer,ethylene-butene copolymer, and ethylene-propylene copolymers all with orwithout controlled tacticity as well as blends of polyolefins havingethyl-propylene-non-conjugated diene terpolymer, rubber-based copolymer,and dynamically vulcanized rubber-based copolymer. Examples of theseinclude products sold under the trade names SANTOPRENE, DYTRON,VISAFLEX, and VYRAM by Advanced Elastomeric Systems of Houston, Tex.,and SARLINK by DSM of Haarlen, the Netherlands.

Examples of rubber-based thermoplastic elastomers include multiblockrubber-based copolymers, particularly those in which the rubber blockcomponent is based on butadiene, isoprene, or ethylene/butylene. Thenon-rubber repeating units of the copolymer may be derived from anysuitable monomers, including meth(acrylate)esters, such as methylmethacrylate and cyclohexylmethacrylate, and vinyl arylenes, such asstyrene. Examples of styrenic copolymers are resins manufactured byKraton Polymers (formerly of Shell Chemicals) under the trade namesKRATON D (for styrene-butadiene-styrene and styrene-isoprene-styrenetypes) and KRATON G (for styrene-ethylene-butylene-styrene andstyrene-ethylene-propylene-styrene types) and Kuraray under the tradename SEPTON. Examples of randomly distributed styrenic polymers includeparamethylstyrene-isobutylene (isobutene) copolymers developed byExxonMobil Chemical Corporation and styrene-butadiene random copolymersdeveloped by Chevron Phillips Chemical Corp.

Examples of copolyester thermoplastic elastomers include polyether esterblock copolymers, polylactone ester block copolymers, and aliphatic andaromatic dicarboxylic acid copolymerized polyesters. Polyether esterblock copolymers are copolymers comprising polyester hard segmentspolymerized from a dicarboxylic acid and a low molecular weight diol,and polyether soft segments polymerized from an alkylene glycol having 2to 10 atoms. Polylactone ester block copolymers are copolymers havingpolylactone chains instead of polyether as the soft segments discussedabove for polyether ester block copolymers. Aliphatic and aromaticdicarboxylic copolymerized polyesters are copolymers of an acidcomponent selected from aromatic dicarboxylic acids, such asterephthalic acid and isophthalic acid, and aliphatic acids having 2 to10 carbon atoms with at least one diol component, selected fromaliphatic and alicyclic diols having 2 to 10 carbon atoms. Blends ofaromatic polyester and aliphatic polyester also may be used for these.Examples of these include products marketed under the trade names HYTRELby E.I. DuPont de Nemours & Company, and SKYPEL by S.K. Chemicals ofSeoul, South Korea.

Examples of other thermoplastic elastomers suitable as additionalpolymer components include those having functional groups, such ascarboxylic acid, maleic anhydride, glycidyl, norbonene, and hydroxylfunctionalities. An example of these includes a block polymer having atleast one polymer block A comprising an aromatic vinyl compound and atleast one polymer block B comprising a conjugated diene compound, andhaving a hydroxyl group at the terminal block copolymer, or itshydrogenated product. An example of this polymer is sold under the tradename SEPTON HG-252 by Kuraray Company of Kurashiki, Japan. Otherexamples of these include: maleic anhydride functionalized triblockcopolymer consisting of polystyrene end blocks andpoly(ethylene/butylene), sold under the trade name KRATON FG 1901X byShell Chemical Company; maleic anhydride modified ethylene-vinyl acetatecopolymer, sold under the trade name FUSABOND by E.I. DuPont de Nemours& Company; ethylene-isobutyl acrylate-methacrylic acid terpolymer, soldunder the trade name NUCREL by E.I. DuPont de Nemours & Company;ethylene-ethyl acrylate-methacrylic anhydride terpolymer, sold under thetrade name BONDINE AX 8390 and 8060 by Sumitomo Chemical Industries;brominated styrene-isobutylene copolymers sold under the trade nameBROMO XP-50 by Exxon Mobil Corporation; and resins having glycidyl ormaleic anhydride functional groups sold under the trade name LOTADER byElf Atochem of Puteaux, France.

Styrenic block copolymers are copolymers of styrene with butadiene,isoprene, or a mixture of the two. Additional unsaturated monomers maybe added to the structure of the styrenic block copolymer as needed forproperty modification of the resulting SBC/urethane copolymer. Thestyrenic block copolymer can be a diblock or a triblock styrenicpolymer. Examples of such styrenic block copolymers are described in,for example, U.S. Pat. No. 5,436,295 to Nishikawa et al. The styrenicblock copolymer can have any known molecular weight for such polymers,and it can possess a linear, branched, star, dendrimeric or combinationmolecular structure. The styrenic block copolymer can be unmodified byfunctional groups, or it can be modified by hydroxyl group, carboxylgroup, or other functional groups, either in its chain structure or atone or more terminus. The styrenic block copolymer can be obtained usingany common process for manufacture of such polymers. The styrenic blockcopolymers also may be hydrogenated using well-known methods to obtain apartially or fully saturated diene monomer block.

Other preferred materials suitable for use as an additional polymers inthe presently disclosed compositions include polyester thermoplasticelastomers marketed under the tradename SKYPEL™ by SK Chemicals of SouthKorea, or diblock or triblock copolymers marketed under the tradenameSEPTON™ by Kuraray Corporation of Kurashiki, Japan, and KRATON™ byKraton Polymers Group of Companies of Chester, United Kingdom. Forexample, SEPTON HG 252 is a triblock copolymer, which has polystyreneend blocks and a hydrogenated polyisoprene midblock and has hydroxylgroups at the end of the polystyrene blocks. HG-252 is commerciallyavailable from Kuraray America Inc. (Houston, Tex.).

Another example of an additional polymer component includes thethermoplastic polyurethanes, which are the reaction product of a diol orpolyol and an isocyanate, with or without a chain extender. Isocyanatesused for making the urethanes encompass diisocyanates andpolyisocyanates. Examples of suitable isocyanates include the following:trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylenediisocyanate, hexamethylene diisocyanate, ethylene diisocyanate,diethylidene diisocyanate, propylene diisocyanate, butylenediisocyanate, bitolylene diisocyanate, tolidine isocyanate, isophoronediisocyanate, dimeryl diisocyanate, dodecane-1,12-diisocyanate,1,10-decamethylene diisocyanate, cyclohexylene-1,2-diisocyanate,1-chlorobenzene-2,4-diisocyanate, furfurylidene diisocyanate,2,4,4-trimethyl hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, dodecamethylene diisocyanate,1,3cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate,1,3-cyclobutane diisocyanate, 1,4-cyclohexane diisocyanate,4,4′-methylenebis(cyclohexyl isocyanate), 4,4′-methylenebis(phenylisocyanate), 1-methyl-2,4-cyclohexane diisocyanate,1-methyl-2,6-cyclohexane diisocyanate, 1,3-bis(isocyanato-methyl)cyclohexane,1,6-diisocyanato-2,2,4,4-tetra-methylhexane,1,6-diisocyanato-2,4,4-tetra-trimethylhexane,trans-cyclohexane-1,4-diisocyanate,3-isocyanato-methyl-3,5,5-trimethylcyclohexyl isocyanate,1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, cyclohexylisocyanate, dicyclohexylmethane 4,4′-diisocyanate,1,4-bis(isocyanatomethyl) cyclohexane, m-phenylene diisocyanate,m-xylylene diisocyanate, m-tetramethylxylylene diisocyanate, p-phenylenediisocyanate, p,p′-biphenyl diisocyanate, 3,3′-dimethyl-4,4′-biphenylenediisocyanate, 3,3′-dimethoxy-4,4′-biphenylene diisocyanate,3,3′-diphenyl-4,4′-biphenylene diisocyanate, 4,4′-biphenylenediisocyanate, 3,3′-dichloro-4,4′-biphenylene diisocyanate,1,5-naphthalene diisocyanate, 4-chloro-1,3-phenylene diisocyanate,1,5-tetrahydronaphthalene diisocyanate, meta-xylene diisocyanate,2,4-toluene diisocyanate, 2,4′-diphenylmethane diisocyanate,2,4-chlorophenylene diisocyanate, 4,4′-diphenylmethane diisocyanate,p,p′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate,2,6-tolylene diisocyanate, 2,2-diphenylpropane-4,4′-diisocyanate,4,4′-toluidine diisocyanate, dianisidine diisocyanate, 4,4′-diphenylether diisocyanate, 1,3-xylylene diisocyanate, 1,4-naphthylenediisocyanate, azobenzene-4,4′-diisocyanate, diphenylsulfone-4,4′-diisocyanate, triphenylmethane 4,4′,4″-triisocyanate,isocyanatoethyl methacrylate,3-isopropenyl-α,α-dimethylbenzyl-isocyanate, dichlorohexamethylenediisocyanate, ω,ω′-diisocyanato-1,4-diethylbenzene, polymethylenepolyphenylene polyisocyanate, polybutylene diisocyanate, isocyanuratemodified compounds, and carbodiimide modified compounds, as well asbiuret modified compounds of the above polyisocyanates. Each isocyanatemay be used either alone or in combination with one or more otherisocyanates. These isocyanate mixtures can include triisocyanates, suchas biuret of hexamethylene diisocyanate and triphenylmethanetriisocyanate, and polyisocyanates, such as polymeric diphenylmethanediisocyanate.

Polyols used for making the polyurethane in the copolymer includepolyester polyols, polyether polyols, polycarbonate polyols andpolybutadiene polyols. Polyester polyols are prepared by condensation orstep-growth polymerization utilizing diacids. Primary diacids forpolyester polyols are adipic acid and isomeric phthalic acids. Adipicacid is used for materials requiring added flexibility, whereas phthalicanhydride is used for those requiring rigidity. Some examples ofpolyester polyols include poly(ethylene adipate) (PEA), poly(diethyleneadipate) (PDA), poly(propylene adipate) (PPA), poly(tetramethyleneadipate) (PBA), poly(hexamethylene adipate) (PHA), poly(neopentyleneadipate) (PNA), polyols composed of 3-methyl-1,5-pentanediol and adipicacid, random copolymer of PEA and PDA, random copolymer of PEA and PPA,random copolymer of PEA and PBA, random copolymer of PHA and PNA,caprolactone polyol obtained by the ring-opening polymerization ofε-caprolactone, and polyol obtained by opening the ring ofβ-methyl-δ-valerolactone with ethylene glycol can be used either aloneor in a combination thereof. Additionally, polyester polyol may becomposed of a copolymer of at least one of the following acids and atleast one of the following glycols. The acids include terephthalic acid,isophthalic acid, phthalic anhydride, oxalic acid, malonic acid,succinic acid, pentanedioic acid, hexanedioic acid, octanedioic acid,nonanedioic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioicacid, dimer acid (a mixture), ρ-hydroxybenzoate, trimellitic anhydride,ε-caprolactone, and β-methyl-δ-valerolactone. The glycols includesethylene glycol, propylene glycol, butylene glycol, pentylene glycol,1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentylene glycol,polyethylene glycol, polytetramethylene glycol, 1,4-cyclohexanedimethanol, pentaerythritol, and 3-methyl-1,5-pentanediol.

Polyether polyols are prepared by the ring-opening additionpolymerization of an alkylene oxide (e.g. ethylene oxide and propyleneoxide) with an initiator of a polyhydric alcohol (e.g. diethyleneglycol), which is an active hydride. Specifically, polypropylene glycol(PPG), polyethylene glycol (PEG) or propylene oxide-ethylene oxidecopolymer can be obtained. Polytetramethylene ether glycol (PTMG) isprepared by the ring-opening polymerization of tetrahydrofuran, producedby dehydration of 1,4-butanediol or hydrogenation of furan.Tetrahydrofuran can form a copolymer with alkylene oxide. Specifically,tetrahydrofuran-propylene oxide copolymer or tetrahydrofuran-ethyleneoxide copolymer can be formed. A polyether polyol may be used eitheralone or in a mixture.

Polycarbonate polyol is obtained by the condensation of a known polyol(polyhydric alcohol) with phosgene, chloroformic acid ester, dialkylcarbonate or diallyl carbonate. A particularly preferred polycarbonatepolyol contains a polyol component using 1,6-hexanediol, 1,4-butanediol,1,3-butanediol, neopentylglycol or 1,5-pentanediol. A polycarbonatepolyol can be used either alone or in a mixture.

Polybutadiene polyol includes liquid diene polymer containing hydroxylgroups, and an average of at least 1.7 functional groups, and may becomposed of diene polymer or diene copolymer having 4 to 12 carbonatoms, or a copolymer of such diene with addition to polymerizableα-olefin monomer having 2 to 2.2 carbon atoms. Specific examples includebutadiene homopolymer, isoprene homopolymer, butadiene-styrenecopolymer, butadiene-isoprene copolymer, butadiene-acrylonitrilecopolymer, butadiene-2-ethyl hexyl acrylate copolymer, andbutadiene-n-octadecyl acrylate copolymer. These liquid diene polymerscan be obtained, for example, by heating a conjugated diene monomer inthe presence of hydrogen peroxide in a liquid reactant. A polybutadienepolyol can be used either alone or in a mixture.

As stated above, the urethane also may incorporate chain extenders.Non-limiting examples of these extenders include polyols, polyaminecompounds, and mixtures of these. Polyol extenders may be primary,secondary, or tertiary polyols. Specific examples of monomers of thesepolyols include: trimethylolpropane (TMP), ethylene glycol,1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol,propylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol,2,3-butanediol, 1,2-pentanediol, 2,3-pentanediol, 2,5-hexanediol,2,4-hexanediol, 2-ethyl-1,3-hexanediol, cyclohexanediol, and2-ethyl-2-(hydroxymethyl)-1,3-propanediol.

Suitable polyamines that may be used as chain extenders include primary,secondary and tertiary amines; polyamines have two or more amines asfunctional groups. Examples of these include: aliphatic diamines, suchas tetramethylenediamine, pentamethylenediamine, hexamethylenediamine;alicyclic diamines, such as 3,3′-dimethyl-4,4′-diamino-dicyclohexylmethane; or aromatic diamines, such as 4,4′-methylenebis-2-chloroaniline, 2,2′,3,3′-tetrachloro-4,4′-diaminophenyl methane,p,p′-methylenedianiline, p-phenylenediamine or 4,4′-diaminodiphenyl; and2,4,6-tris(dimethylaminomethyl)phenol. Aromatic diamines have a tendencyto provide a stiffer product than aliphatic or cycloaliphatic diamines.A chain extender may be used either alone or in a mixture.

In yet another embodiment, a blend of an ionomer and a block copolymercan be included in the composition that includes the polyalkenamerrubber or polyalkenamer/polyamide, or the blend of an ionomer and ablock copolymer can be included in a core or layer that does not includethe polyalkenamer rubber to polyalkenamer/polyamide composition. Theblend of an ionomer and a block copolymer can be particularly includedin the mantle layer. An example of a block copolymer is a functionalizedstyrenic block copolymer, the block copolymer incorporating a firstpolymer block having an aromatic vinyl compound, a second polymer blockhaving a conjugated diene compound, and a hydroxyl group located at ablock copolymer, or its hydrogenation product, in which the ratio ofblock copolymer to ionomer ranges from 5:95 to 95:5 by weight, morepreferably from about 10:90 to about 90:10 by weight, more preferablyfrom about 20:80 to about 80:20 by weight, more preferably from about30:70 to about 70:30 by weight and most preferably from about 35:65 toabout 65:35 by weight. A preferred block copolymer is SEPTON HG-252.Such blends are described in more detail in commonly-assigned U.S. Pat.No. 6,861,474 and U.S. Patent publication No. 2003/0224871 both of whichare incorporated herein by reference in their entireties.

In a further embodiment, the core, mantle and/or cover layers (andparticularly a mantle layer) can comprise a composition prepared byblending together at least three materials, identified as Components A,B, and C, and melt-processing these components to form in-situ a polymerblend composition incorporating a pseudo-crosslinked polymer network.Such blends are described in more detail in commonly-assigned U.S. Pat.No. 6,930,150, which is incorporated by reference herein in itsentirety. Component A is a monomer, oligomer, prepolymer or polymer thatincorporates at least five percent by weight of at least one type of ananionic functional group, and more preferably between about 5% and 50%by weight. Component B is a monomer, oligomer, or polymer thatincorporates less by weight of anionic functional groups than doesComponent A, Component B preferably incorporates less than about 25% byweight of anionic functional groups, more preferably less than about 20%by weight, more preferably less than about 10% by weight, and mostpreferably Component B is free of anionic functional groups. Component Cincorporates a metal cation, preferably as a metal salt. Thepseudo-crosslinked network structure is formed in-situ, not by covalentbonds, but instead by ionic clustering of the reacted functional groupsof Component A. The method can incorporate blending together more thanone of any of Components A, B, or C.

The polymer blend can include either Component A or B dispersed in aphase of the other. Preferably, blend compositions comprises betweenabout 1% and about 99% by weight of Component A based on the combinedweight of Components A and B, more preferably between about 10% andabout 90%, more preferably between about 20% and about 80%, and mostpreferably, between about 30% and about 70%. Component C is present in aquantity sufficient to produce the preferred amount of reaction of theanionic functional groups of Component A after sufficientmelt-processing. Preferably, after melt-processing at least about 5% ofthe anionic functional groups in the chemical structure of Component Ahave been consumed, more preferably between about 10% and about 90%,more preferably between about 10% and about 80%, and most preferablybetween about 10% and about 70%.

The composition preferably is prepared by mixing the above materialsinto each other thoroughly, either by using a dispersive mixingmechanism, a distributive mixing mechanism, or a combination of these.These mixing methods are well known in the manufacture of polymerblends. As a result of this mixing, the anionic functional group ofComponent A is dispersed evenly throughout the mixture. Next, reactionis made to take place in-situ at the site of the anionic functionalgroups of Component A with Component C in the presence of Component B.This reaction is prompted by addition of heat to the mixture. Thereaction results in the formation of ionic clusters in Component A andformation of a pseudo-crosslinked structure of Component A in thepresence of Component B. Depending upon the structure of Component B,this pseudo-crosslinked Component A can combine with Component B to forma variety of interpenetrating network structures. For example, thematerials can form a pseudo-crosslinked network of Component A dispersedin the phase of Component B, or Component B can be dispersed in thephase of the pseudo-crosslinked network of Component A. Component B mayor may not also form a network, depending upon its structure, resultingin either: a fully-interpenetrating network, i.e., two independentnetworks of Components A and B penetrating each other, but notcovalently bonded to each other; or, a semi-interpenetrating network ofComponents A and B, in which Component B forms a linear, grafted, orbranched polymer interspersed in the network of Component A. Forexample, a reactive functional group or an unsaturation in Component Bcan be reacted to form a crosslinked structure in the presence of thein-situ-formed, pseudo-crosslinked structure of component A, leading toformation of a fully-interpenetrating network. Any anionic functionalgroups in Component B also can be reacted with the metal cation ofComponent C, resulting in pseudo-crosslinking via ionic clusterattraction of Component A to Component B.

The level of in-situ-formed pseudo-crosslinking in the compositionsformed by the present methods can be controlled as desired by selectionand ratio of Components A and B, amount and type of anionic functionalgroup, amount and type of metal cation in Component C, type and degreeof chemical reaction in Component B, and degree of pseudo-crosslinkingproduced of Components A and B.

As discussed above, the mechanical and thermal properties of the polymerblend for the inner mantle layer and/or the outer mantle layer can becontrolled as required by a modifying any of a number of factors,including: chemical structure of Components A and B, particularly theamount and type of anionic functional groups; mean molecular weight andmolecular weight distribution of Components A and B; linearity andcrystallinity of Components A and B; type of metal cation in componentC; degree of reaction achieved between the anionic functional groups andthe metal cation; mix ratio of Component A to Component B; type anddegree of chemical reaction in Component B; presence of chemicalreaction, such as a crosslinking reaction, between Components A and B;and the particular mixing methods and conditions used.

As discussed above, Component A can be any monomer, oligomer,prepolymer, or polymer incorporating at least 5% by weight of anionicfunctional groups. Those anionic functional groups can be incorporatedinto monomeric, oligomeric, prepolymeric, or polymeric structures duringthe synthesis of Component A, or they can be incorporated into apre-existing monomer, oligomer, prepolymer, or polymer throughsulfonation, phosphonation, or carboxylation to produce Component A.

Preferred, but non-limiting, examples of suitable copolymers andterpolymers include copolymers or terpolymers of: ethylene/acrylic acid,ethylene/methacrylic acid, ethylene/itaconic acid, ethylene/methylhydrogen maleate, ethylene/maleic acid, ethylene/methacrylicacid/ethylacrylate, ethylene/itaconic acid/methyl metacrylate,ethylene/methyl hydrogen maleate/ethyl acrylate, ethylene/methacrylicacid/vinyl acetate, ethylene/acrylic acid/vinyl alcohol,ethylene/propylene/acrylic acid, ethylene/styrene/acrylic acid,ethylene/methacrylic acid/acrylonitrile, ethylene/fumaric acid/vinylmethyl ether, ethylene/vinyl chloride/acrylic acid, ethylene/vinyldienechloride/acrylic acid, ethylene/vinyl fluoride/methacrylic acid, andethylene/chlorotrifluoroethylene/methacrylic acid, or anymetallocene-catalyzed polymers of the above-listed species.

Another family of thermoplastic elastomers for use in the golf balls arepolymers of i) ethylene and/or an alpha olefin; and ii) an α,β-ethylenically unsaturated C₃-C₂₀ carboxylic acid or anhydride, or anα, β-ethylenically unsaturated C₃-C₂₀ sulfonic acid or anhydride or anα, β-ethylenically unsaturated C₃-C₂₀ phosphoric acid or anhydride and,optionally iii) a C₁-C₁₀ ester of an α, β-ethylenically unsaturatedC₃-C₂₀ carboxylic acid or a C₁-C₁₀ ester of an α, β-ethylenicallyunsaturated C₃-C₂₀ sulfonic acid or a C₁-C₁₀ ester of an α,β-ethylenically unsaturated C₃-C₂₀ phosphoric acid.

Preferably, the alpha-olefin has from 2 to 10 carbon atoms and ispreferably ethylene, and the unsaturated carboxylic acid is a carboxylicacid having from about 3 to 8 carbons. Examples of such acids includeacrylic acid, methacrylic acid, ethacrylic acid, chloroacrylic acid,crotonic acid, maleic acid, fumaric acid, and itaconic acid, withacrylic acid being preferred. Preferably, the carboxylic acid ester ofif present may be selected from the group consisting of vinyl esters ofaliphatic carboxylic acids wherein the acids have 2 to 10 carbon atomsand vinyl ethers wherein the alkyl groups contain 1 to 10 carbon atoms.

Examples of such polymers suitable for use as include, but are notlimited to, an ethylene/acrylic acid copolymer, an ethylene/methacrylicacid copolymer, an ethylene/itaconic acid copolymer, an ethylene/maleicacid copolymer, an ethylene/methacrylic acid/vinyl acetate copolymer, anethylene/acrylic acid/vinyl alcohol copolymer, and the like.

Most preferred are ethylene/(meth)acrylic acid copolymers andethylene/(meth)acrylic acid/alkyl (meth)acrylate terpolymers, orethylene and/or propylene maleic anhydride copolymers and terpolymers.

The acid content of the polymer may contain anywhere from 1 to 30percent by weight acid. In some instances, it is preferable to utilize ahigh acid copolymer (i.e., a copolymer containing greater than 16% byweight acid, preferably from about 17 to about 25 weight percent acid,and more preferably about 20 weight percent acid).

Examples of such polymers which are commercially available include, butare not limited to, the Escor® 5000, 5001, 5020, 5050, 5070, 5100, 5110and 5200 series of ethylene-acrylic acid copolymers sold by Exxon andthe PRIMACOR® 1321, 1410, 1410-XT, 1420, 1430, 2912, 3150, 3330, 3340,3440, 3460, 4311, 4608 and 5980 series of ethylene-acrylic acidcopolymers sold by The Dow Chemical Company, Midland, Mich.

Also included are the bimodal ethylene/carboxylic acid polymers asdescribed in U.S. Pat. No. 6,562,906. These polymers compriseethylene/α, β-ethylenically unsaturated C₃₋₈ carboxylic acid highcopolymers, particularly ethylene (meth)acrylic acid copolymers andethylene, alkyl (meth)acrylate, (meth)acrylic acid terpolymers, havingmolecular weights of about 80,000 to about 500,000 which are meltblended with ethylene/α, β-ethylenically unsaturated C₃₋₈ carboxylicacid copolymers, particularly ethylene/(meth)acrylic acid copolymershaving molecular weights of about 2,000 to about 30,000.

As discussed above, Component B can be any monomer, oligomer, orpolymer, preferably having a lower weight percentage of anionicfunctional groups than that present in Component A in the weight rangesdiscussed above, and most preferably free of such functional groups.Examples of suitable materials for Component B include, but are notlimited to, the following: thermoplastic elastomer, thermoset elastomer,synthetic rubber, thermoplastic vulcanizate, copolymeric ionomer,terpolymeric ionomer, polycarbonate, polyolefin, polyamide, copolymericpolyamide, polyesters, polyvinyl alcohols,acrylonitrile-butadiene-styrene copolymers, polyurethane, polyarylate,polyacrylate, polyphenyl ether, modified-polyphenyl ether, high-impactpolystyrene, diallyl phthalate polymer, metallocene catalyzed polymers,acrylonitrile-styrene-butadiene (ABS), styrene-acrylonitrile (SAN)(including olefin-modified SAN and acrilonitrile styrene acrylonitrile),styrene-maleic anhydryde (S/MA) polymer, styrenic copolymer,functionalized styrenic copolymer, functionalized styrenic terpolymer,styrenic terpolymer, cellulose polymer, liquid crystal polymer (LCP),ehtylene-propylene-diene terpolymer (EPDM), ethylene-propylenecopolymer, ethylene vinyl acetate, polyurea, and polysiloxane or anymetallocene-catalyzed polymers of these species. Particularly suitablepolymers for use as Component B include polyethylene-terephthalate,polybutyleneterephthalate, polytrimethylene-terephthalate,ethylene-carbon monoxide copolymer, polyvinyl-diene fluorides,polyphenylenesulfide, polypropyleneoxide, polyphenyloxide,polypropylene, functionalized polypropylene, polyethylene,ethylene-octene copolymer, ethylene-methyl acrylate, ethylene-butylacrylate, polycarbonate, polysiloxane, functionalized polysiloxane,copolymeric ionomer, terpolymeric ionomer, polyetherester elastomer,polyesterester elastomer, polyetheramide elastomer, propylene-butadienecopolymer, modified copolymer of ethylene and propylene, styreniccopolymer (including styrenic block copolymer and randomly distributedstyrenic copolymer, such as styrene-isobutylene copolymer andstyrene-butadiene copolymer), partially or fully hydrogenatedstyrene-butadiene-styrene block copolymers such asstyrene-(ethylene-propylene)-styrene orstyrene-(ethylene-butylene)-styrene block copolymers, partially or fullyhydrogenated styrene-butadiene-styrene block copolymers with functionalgroup, polymers based on ethylene-propylene-(diene), polymers based onfunctionalized ethylene-propylene-diene), dynamically vulcanizedpolypropylene/ethylene-propylene-diene-copolymer, thermoplasticvulcanizates based on ethylene-propylene-(diene), thermoplasticpolyetherurethane, thermoplastic polyesterurethane, compositions formaking thermoset polyurethane, thermoset polyurethane, natural rubber,styrene-butadiene rubber, nitrile rubber, chloroprene rubber,fluorocarbon rubber, butyl rubber, acrylic rubber, silicone rubber,chlorosulfonated polyethylene, polyisobutylene, alfin rubber, polyesterrubber, epichlorphydrin rubber, chlorinated isobutylene-isoprene rubber,nitrile-isobutylene rubber, 1,2-polybutadiene, 1,4-polybutadiene,cis-polyisoprene, trans-polyisoprene, and polybutylene-octene.

Preferred materials for use as Component B include polyester elastomersmarketed under the name PEBAX and LOTADER marketed by ATOFINA Chemicalsof Philadelphia, Pa.; HYTREL, FUSABOND, and NUCREL marketed by E.I.DuPont de Nemours & Co. of Wilmington, Del.; SKYPEL and SKYTHANE by S.K.Chemicals of Seoul, South Korea; SEPTON and HYBRAR marketed by KurarayCompany of Kurashiki, Japan; ESTHANE by Noveon; and KRATON marketed byKraton Polymers. A most preferred material for use as Component B isSEPTON HG-252

As stated above, Component C is a metal cation. These metals are fromgroups IA, IB, IIA, IIB, IIIA, IIIB, IVA, IVB, VA, VB, VIA, VIB, VIIBand VIIIB of the periodic table. Examples of these metals includelithium, sodium, magnesium, aluminum, potassium, calcium, manganese,tungsten, titanium, iron, cobalt, nickel, hafnium, copper, zinc, barium,zirconium, and tin. Suitable metal compounds for use as a source ofComponent C are, for example, metal salts, preferably metal hydroxides,metal carbonates, or metal acetates. In addition to Components A, B, andC, other materials commonly used in polymer blend compositions, can beincorporated into compositions prepared using these methods, including:crosslinking agents, co-crosslinking agents, accelerators, activators,UV-active chemicals such as UV initiators, EB-active chemicals,colorants, UV stabilizers, optical brighteners, antioxidants, processingaids, mold release agents, foaming agents, and organic, inorganic ormetallic fillers or fibers, including fillers to adjust specificgravity.

Various known methods are suitable for preparation of polymer blends.For example, the three components can be premixed together in any typeof suitable mixer, such as a V-blender, tumbler mixer, or blade mixer.This premix then can be melt-processed using an internal mixer, such asBanbury mixer, roll-mill or combination of these, to produce a reactionproduct of the anionic functional groups of Component A by Component Cin the presence of Component B. Alternatively, the premix can bemelt-processed using an extruder, such as single screw, co-rotating twinscrew, or counter-rotating twin screw extruder, to produce the reactionproduct. The mixing methods discussed above can be used together tomelt-mix the three components to prepare the compositions of the presentinvention. Also, the components can be fed into an extrudersimultaneously or sequentially.

Most preferably, Components A and B are melt-mixed together withoutComponent C, with or without the premixing discussed above, to produce amelt-mixture of the two components. Then, Component C separately ismixed into the blend of Components A and B. This mixture is melt-mixedto produce the reaction product. This two-step mixing can be performedin a single process, such as, for example, an extrusion process using aproper barrel length or screw configuration, along with a multiplefeeding system. In this case, Components A and B can be fed into theextruder through a main hopper to be melted and well-mixed while flowingdownstream through the extruder. Then Component C can be fed into theextruder to react with the mixture of Components A and B between thefeeding port for component C and the die head of the extruder. The finalpolymer composition then exits from the die. If desired, any extra stepsof melt-mixing can be added to either approach of the method of thepresent invention to provide for improved mixing or completion of thereaction between A and C. Also, additional components discussed abovecan be incorporated either into a premix, or at any of the melt-mixingstages. Alternatively, Components A, B, and C can be melt-mixedsimultaneously to form in-situ a pseudo-crosslinked structure ofComponent A in the presence of Component B, either as a fully orsemi-interpenetrating network.

In addition to the polyalkenamer rubber/polyamide composition, orpolyalkenamer rubber composition, the core, cover layer and, optionally,one or more inner cover layers golf ball may further comprise one ormore ionomer resins. One family of such resins were developed in themid-1960's, by E.I. DuPont de Nemours and Co., and sold under thetrademark SURLYN®. Preparation of such ionomers is well known, forexample see U.S. Pat. No. 3,264,272. Generally speaking, most commercialionomers are unimodal and consist of a polymer of a mono-olefin, e.g.,an alkene, with an unsaturated mono- or dicarboxylic acids having 3 to12 carbon atoms. An additional monomer in the form of a mono- ordicarboxylic acid ester may also be incorporated in the formulation as aso-called “softening comonomer”. The incorporated carboxylic acid groupsare then neutralized by a basic metal ion salt, to form the ionomer. Themetal cations of the basic metal ion salt used for neutralizationinclude Li⁺, Na⁺, K⁺, Zn²⁺, Ca²⁺, Co²⁺, Ni²⁺, Cu²⁺, Pb²⁺, and Mg²⁺, withthe Li⁺, Na⁺, Ca²⁺, Zn²⁺, and Mg²⁺ being preferred. The basic metal ionsalts include those of for example formic acid, acetic acid, nitricacid, and carbonic acid, hydrogen carbonate salts, oxides, hydroxides,and alkoxides.

The first commercially available ionomer resins contained up to 16weight percent acrylic or methacrylic acid, although it was also wellknown at that time that, as a general rule, the hardness of these covermaterials could be increased with increasing acid content. Hence, inResearch Disclosure 29703, published in January 1989, DuPont disclosedionomers based on ethylene/acrylic acid or ethylene/methacrylic acidcontaining acid contents of greater than 15 weight percent. In this samedisclosure, DuPont also taught that such so called “high acid ionomers”had significantly improved stiffness and hardness and thus could beadvantageously used in golf ball construction, when used either singlyor in a blend with other ionomers.

More recently, high acid ionomers are typically defined as those ionomerresins with acrylic or methacrylic acid units present from 16 wt. % toabout 35 wt. % in the polymer. Generally, such a high acid ionomer willhave a flexural modulus from about 50,000 psi to about 125,000 psi.

Ionomer resins further comprising a softening comonomer, present fromabout 10 wt. % to about 50 wt. % in the polymer, have a flexural modulusfrom about 2,000 psi to about 10,000 psi, and are sometimes referred toas “soft” or “very low modulus” ionomers. Typical softening comonomersinclude n-butyl acrylate, iso-butyl acrylate, n-butyl methacrylate,methyl acrylate and methyl methacrylate.

Today, there are a wide variety of commercially available ionomer resinsbased both on copolymers of ethylene and (meth)acrylic acid orterpolymers of ethylene and (meth)acrylic acid and (meth)acrylate, allof which many of which are be used as a golf ball component. Theproperties of these ionomer resins can vary widely due to variations inacid content, softening comonomer content, the degree of neutralization,and the type of metal ion used in the neutralization. The full rangecommercially available typically includes ionomers of polymers ofgeneral formula, E/X/Y polymer, wherein E is ethylene, X is a C₃ to C₈α,β ethylenically unsaturated carboxylic acid, such as acrylic ormethacrylic acid, and is present in an amount from about 2 to about 30weight % of the E/X/Y copolymer, and Y is a softening comonomer selectedfrom the group consisting of alkyl acrylate and alkyl methacrylate, suchas methyl acrylate or methyl methacrylate, and wherein the alkyl groupshave from 1-8 carbon atoms, Y is in the range of 0 to about 50 weight %of the E/X/Y copolymer, and wherein the acid groups present in saidionomeric polymer are partially neutralized with a metal selected fromthe group consisting of zinc, sodium, lithium, calcium, magnesium, andcombinations thereof.

E/X/Y, where E is ethylene, X is a softening comonomer such as presentin an amount of from 0 wt. % to about 50 wt. % of the polymer, and Y ispresent in an amount from about 5 wt. % to about 35 wt. % of thepolymer, and wherein the acid moiety is neutralized from about 1% toabout 90% to form an ionomer with a cation such as lithium, sodium,potassium, magnesium, calcium, barium, lead, tin, zinc or aluminum, or acombination of such cations.

The ionomer may also be a so-called bimodal ionomer as described in U.S.Pat. No. 6,562,906 (the entire contents of which are herein incorporatedby reference). These ionomers are bimodal as they are prepared fromblends comprising polymers of different molecular weights. Specificallythey include bimodal polymer blend compositions comprising:

-   -   a) a high molecular weight component having molecular weight of        about 80,000 to about 500,000 and comprising one or more        ethylene/α, β-ethylenically unsaturated C₃₋₈ carboxylic acid        copolymers and/or one or more ethylene, alkyl (meth)acrylate,        (meth)acrylic acid terpolymers; said high molecular weight        component being partially neutralized with metal ions selected        from the group consisting of lithium, sodium, zinc, calcium,        magnesium, and a mixture of any these; and    -   b) a low molecular weight component having a molecular weight of        about from about 2,000 to about 30,000 and comprising one or        more ethylene/α, β-ethylenically unsaturated C₃₋₈ carboxylic        acid copolymers and/or one or more ethylene, alkyl        (meth)acrylate, (meth)acrylic acid terpolymers; said low        molecular weight component being partially neutralized with        metal ions selected from the group consisting of lithium,        sodium, zinc, calcium, magnesium, and a mixture of any these.

In addition to the unimodal and bimodal ionomers, also included are theso-called “modified ionomers” examples of which are described in U.S.Pat. Nos. 6,100,321, 6,329,458 and 6,616,552 and U.S. Patent PublicationUS 2003/0158312 A1, the entire contents of all of which are hereinincorporated by reference.

The modified unimodal ionomers may be prepared by mixing:

-   -   a) an ionomeric polymer comprising ethylene, from 5 to 25 weight        percent (meth)acrylic acid, and from 0 to 40 weight percent of a        (meth)acrylate monomer, said ionomeric polymer neutralized with        metal ions selected from the group consisting of lithium,        sodium, zinc, calcium, magnesium, and a mixture of any of these;        and    -   b) from about 5 to about 40 weight percent (based on the total        weight of said modified ionomeric polymer) of one or more fatty        acids or metal salts of said fatty acid, the metal selected from        the group consisting of calcium, sodium, zinc, potassium, and        lithium, barium and magnesium and the fatty acid preferably        being stearic acid.

The modified bimodal ionomers, which are ionomers derived from theearlier described bimodal ethylene/carboxylic acid polymers (asdescribed in U.S. Pat. No. 6,562,906, the entire contents of which areherein incorporated by reference), are prepared by mixing;

-   -   a) a high molecular weight component having molecular weight of        about 80,000 to about 500,000 and comprising one or more        ethylene/α, β-ethylenically unsaturated C₃₋₈ carboxylic acid        copolymers and/or one or more ethylene, alkyl (meth)acrylate,        (meth)acrylic acid terpolymers; said high molecular weight        component being partially neutralized with metal ions selected        from the group consisting of lithium, sodium, zinc, calcium,        potassium, magnesium, and a mixture of any of these; and    -   b) a low molecular weight component having a molecular weight of        about from about 2,000 to about 30,000 and comprising one or        more ethylene/α, β-ethylenically unsaturated C₃₋₈ carboxylic        acid copolymers and/or one or more ethylene, alkyl        (meth)acrylate, (meth)acrylic acid terpolymers; said low        molecular weight component being partially neutralized with        metal ions selected from the group consisting of lithium,        sodium, zinc, calcium, potassium, magnesium, and a mixture of        any of these; and    -   c) from about 5 to about 40 weight percent (based on the total        weight of said modified ionomeric polymer) of one or more fatty        acids or metal salts of said fatty acid, the metal selected from        the group consisting of calcium, sodium, zinc, potassium and        lithium, barium and magnesium and the fatty acid preferably        being stearic acid.

The fatty or waxy acid salts utilized in the various modified ionomersare composed of a chain of alkyl groups containing from about 4 to 75carbon atoms (usually even numbered) and characterized by a —COOHterminal group. The generic formula for all fatty and waxy acids aboveacetic acid is CH₃ (CH₂)_(X) COOH, wherein the carbon atom countincludes the carboxyl group. The fatty or waxy acids utilized to producethe fatty or waxy acid salts modifiers may be saturated or unsaturated,and they may be present in solid, semi-solid or liquid form.

Examples of suitable saturated fatty acids, i.e., fatty acids in whichthe carbon atoms of the alkyl chain are connected by single bonds,include but are not limited to stearic acid (C₁₈, i.e., CH₃ (CH₂)₁₆COOH), palmitic acid (C₁₆, i.e., CH₃ (CH₂)₁₄ COOH), pelargonic acid (C₉,i.e., CH₃ (CH₂)₇ COOH) and lauric acid (C₁₂, i.e., CH₃ (CH₂)₁₀ OCOOH).Examples of suitable unsaturated fatty acids, i.e., a fatty acid inwhich there are one or more double bonds between the carbon atoms in thealkyl chain, include but are not limited to oleic acid (C₁₃, i.e., CH₃(CH₂)₇ CH:CH(CH₂)₇ COOH).

The source of the metal ions used to produce the metal salts of thefatty or waxy acid salts used in the various modified ionomers aregenerally various metal salts which provide the metal ions capable ofneutralizing, to various extents, the carboxylic acid groups of thefatty acids. These include the sulfate, carbonate, acetate andhydroxylate salts of zinc, barium, calcium and magnesium.

Since the fatty acid salts modifiers comprise various combinations offatty acids neutralized with a large number of different metal ions,several different types of fatty acid salts may be utilized in theinvention, including metal stearates, laureates, oleates, andpalmitates, with calcium, zinc, sodium, lithium, potassium and magnesiumstearate being preferred, and calcium and sodium stearate being mostpreferred.

The fatty or waxy acid or metal salt of said fatty or waxy acid ispresent in the modified ionomeric polymers in an amount of from about 5to about 40, preferably from about 7 to about 35, more preferably fromabout 8 to about 20 weight percent (based on the total weight of saidmodified ionomeric polymer).

As a result of the addition of the one or more metal salts of a fatty orwaxy acid, from about 40 to 100, preferably from about 50 to 100, morepreferably from about 70 to 100 percent of the acidic groups in thefinal modified ionomeric polymer composition are neutralized by a metalion.

An example of such a modified ionomer polymer is DuPont® HPF-1000available from E. I. DuPont de Nemours and Co. Inc.

A preferred ionomer composition may be prepared by blending one or moreof the unimodal ionomers, bimodal ionomers, or modified unimodal orbimodal ionomeric polymers as described herein, and further blended witha zinc neutralized ionomer of a polymer of general formula E/X/Y where Eis ethylene, X is a softening comonomer such as acrylate or methacrylateand is present in an amount of from 0 to about 50, preferably 0 to about25, most preferably 0, and Y is acrylic or methacrylic acid and ispresent in an amount from about 5 wt. % to about 25, preferably fromabout 10 to about 25, and most preferably about 10 to about 20 wt % ofthe total composition.

The polyalkenamer rubber/polyamide compositions, or polyalkenamer rubbercomposition, used to prepare the golf balls can also incorporate one ormore fillers. Such fillers are typically in a finely divided form, forexample, in a size generally less than about 20 mesh, preferably lessthan about 100 mesh U.S. standard size, except for fibers and flock,which are generally elongated. Flock and fiber sizes should be smallenough to facilitate processing. Filler particle size will depend upondesired effect, cost, ease of addition, and dusting considerations. Theappropriate amounts of filler required will vary depending on theapplication but typically can be readily determined without undueexperimentation.

The filler preferably is selected from the group consisting ofprecipitated hydrated silica, limestone, clay, talc, asbestos, barytes,glass fibers, aramid fibers, mica, calcium metasilicate, barium sulfate,zinc sulfide, lithopone, silicates, silicon carbide, diatomaceous earth,carbonates such as calcium or magnesium or barium carbonate, sulfatessuch as calcium or magnesium or barium sulfate, metals, includingtungsten steel copper, cobalt or iron, metal alloys, tungsten carbide,metal oxides, metal stearates, and other particulate carbonaceousmaterials, and any and all combinations thereof. Preferred examples offillers include metal oxides, such as zinc oxide and magnesium oxide. Inanother preferred embodiment the filler comprises a continuous ornon-continuous fiber. In another preferred embodiment the fillercomprises one or more so called nanofillers, as described in U.S. Pat.No. 6,794,447 and U.S. Patent Publication No. 2004-0092336A1 publishedMay 13, 2004 and U.S. Patent Publication No. 2005-0059756A1 publishedMar. 17, 2005, the entire contents of each of which are hereinincorporated by reference.

Inorganic nanofiller material generally is made of clay, such ashydrotalcite, phyllosilicate, saponite, hectorite, beidellite,stevensite, vermiculite, halloysite, mica, montmorillonite,micafluoride, or octosilicate. To facilitate incorporation of thenanofiller material into a polymer material, either in preparingnanocomposite materials or in preparing polymer-based golf ballcompositions, the clay particles generally are coated or treated by asuitable compatibilizing agent. The compatibilizing agent allows forsuperior linkage between the inorganic and organic material, and it alsocan account for the hydrophilic nature of the inorganic nanofillermaterial and the possibly hydrophobic nature of the polymer.Compatibilizing agents may exhibit a variety of different structuresdepending upon the nature of both the inorganic nanofiller material andthe target matrix polymer. Non-limiting examples include hydroxy-,thiol-, amino-, epoxy-, carboxylic acid-, ester-, amide-, andsiloxy-group containing compounds, oligomers or polymers. The nanofillermaterials can be incorporated into the polymer either by dispersion intothe particular monomer or oligomer prior to polymerization, or by meltcompounding of the particles into the matrix polymer. Examples ofcommercial nanofillers are various Cloisite grades including 10A, 15A,20A, 25A, 30B, and NA+ of Southern Clay Products (Gonzales, Tex.) andthe Nanomer grades including 1.24TL and C.30EVA of Nanocor, Inc.(Arlington Heights, Ill.).

As mentioned above, the nanofiller particles have an aggregate structurewith the aggregates particle sizes in the micron range and above.However, these aggregates have a stacked plate structure with theindividual platelets being roughly 1 nanometer (nm) thick and 100 to1000 nm across. As a result, nanofillers have extremely high surfacearea, resulting in high reinforcement efficiency to the material at lowloading levels of the particles. The sub-micron-sized particles enhancethe stiffness of the material, without increasing its weight or opacityand without reducing the material's low-temperature toughness.

Nanofillers when added into a matrix polymer, such as the polyalkenamerrubber/polyamide composition, can be mixed in three ways. In one type ofmixing there is dispersion of the aggregate structures within the matrixpolymer, but on mixing no interaction of the matrix polymer with theaggregate platelet structure occurs, and thus the stacked plateletstructure is essentially maintained. As used herein, this type of mixingis defined as “undispersed”.

However, if the nanofiller material is selected correctly, the matrixpolymer chains can penetrate into the aggregates and separate theplatelets, and thus when viewed by transmission electron microscopy orx-ray diffraction, the aggregates of platelets are expanded. At thispoint the nanofiller is said to be substantially evenly dispersed withinand reacted into the structure of the matrix polymer. This level ofexpansion can occur to differing degrees. If small amounts of the matrixpolymer are layered between the individual platelets then, as usedherein, this type of mixing is known as “intercalation”.

In some cases, further penetration of the matrix polymer chains into theaggregate structure separates the platelets, and leads to a completebreaking up of the platelet's stacked structure in the aggregate andthus when viewed by transmission electron microscopy (TEM), theindividual platelets are thoroughly mixed throughout the matrix polymer.As used herein, this type of mixing is known as “exfoliated”. Anexfoliated nanofiller has the platelets fully dispersed throughout thepolymer matrix; the platelets may be dispersed unevenly but preferablyare dispersed evenly.

While not wishing to be limited to any theory, one possible explanationof the differing degrees of dispersion of such nanofillers within thematrix polymer structure is the effect of the compatibilizer surfacecoating on the interaction between the nanofiller platelet structure andthe matrix polymer. By careful selection of the nanofiller it ispossible to vary the penetration of the matrix polymer into the plateletstructure of the nanofiller on mixing. Thus, the degree of interactionand intrusion of the polymer matrix into the nanofiller controls theseparation and dispersion of the individual platelets of the nanofillerwithin the polymer matrix. This interaction of the polymer matrix andthe platelet structure of the nanofiller is defined herein as thenanofiller “reacting into the structure of the polymer” and thesubsequent dispersion of the platelets within the polymer matrix isdefined herein as the nanofiller “being substantially evenly dispersed”within the structure of the polymer matrix.

If no compatibilizer is present on the surface of a filler such as aclay, or if the coating of the clay is attempted after its addition tothe polymer matrix, then the penetration of the matrix polymer into thenanofiller is much less efficient, very little separation and nodispersion of the individual clay platelets occurs within the matrixpolymer.

As used herein, a “nanocomposite” is defined as a polymer matrix havingnanofiller intercalated or exfoliated within the matrix. Physicalproperties of the polymer will change with the addition of nanofillerand the physical properties of the polymer are expected to improve evenmore as the nanofiller is dispersed into the polymer matrix to form ananocomposite.

Materials incorporating nanofiller materials can provide these propertyimprovements at much lower densities than those incorporatingconventional fillers. For example, a nylon-6 nanocomposite materialmanufactured by RTP Corporation of Wichita, Kans. uses a 3% to 5% clayloading and has a tensile strength of 11,800 psi and a specific gravityof 1.14, while a conventional 30% mineral-filled material has a tensilestrength of 8,000 psi and a specific gravity of 1.36. Because use ofnanocomposite materials with lower loadings of inorganic materials thanconventional fillers provides the same properties, this use allowsproducts to be lighter than those with conventional fillers, whilemaintaining those same properties.

Nanocomposite materials are materials incorporating from about 0.1% toabout 20%, preferably from about 0.1% to about 15%, and most preferablyfrom about 0.1% to about 10% of nanofiller reacted into andsubstantially dispersed through intercalation or exfoliation into thestructure of an organic material, such as a polymer, to providestrength, temperature resistance, and other property improvements to theresulting composite. Descriptions of particular nanocomposite materialsand their manufacture can be found in U.S. Pat. No. 5,962,553 toEllsworth, U.S. Pat. No. 5,385,776 to Maxfield et al., and U.S. Pat. No.4,894,411 to Okada et al. Examples of nanocomposite materials currentlymarketed include M1030D, manufactured by Unitika Limited, of Osaka,Japan, and 1015C2, manufactured by UBE America of New York, N.Y.

When nanocomposites are blended with other polymer systems, thenanocomposite may be considered a type of nanofiller concentrate.However, a nanofiller concentrate may be more generally a polymer intowhich nanofiller is mixed; a nanofiller concentrate does not requirethat the nanofiller has reacted and/or dispersed evenly into the carrierpolymer.

Preferably the nanofiller material is added to the polyalkenamerrubber/polyamide composition in an amount of from about 0.1% to about20%, preferably from about 0.1% to about 15%, and most preferably fromabout 0.1% to about 10% by weight of nanofiller reacted into andsubstantially dispersed through intercalation or exfoliation into thestructure of the polyalkenamer/polyamide composition.

If desired, the various polymer compositions used to prepare the golfballs can additionally contain other additives such as plasticizers,pigments, antioxidants, U.V. absorbers, optical brighteners, or anyother additives generally employed in plastics formulation or thepreparation of golf balls.

Another particularly well-suited additive for use in the presentlydisclosed compositions includes compounds having the general formula:(R₂N)_(m)—R′—(X(O)_(n)OR_(y))_(m),where R is hydrogen, or a C₁-C₂₀ aliphatic, cycloaliphatic or aromaticsystems; R′ is a bridging group comprising one or more C₁-C₂₀ straightchain or branched aliphatic or alicyclic groups, or substituted straightchain or branched aliphatic or alicyclic groups, or aromatic group, oran oligomer of up to 12 repeating units including, but not limited to,polypeptides derived from an amino acid sequence of up to 12 aminoacids; and X is C or S or P with the proviso that when X=C, n=1 and y=1and when X=S, n=2 and y=1, and when X=P, n=2 and y=2. Also, m=1-3. Thesematerials are more fully described in copending U.S. Provisional PatentApplication No. 60/588,603, filed on Jul. 16, 2004, the entire contentsof which are herein incorporated by reference. These materials includecaprolactam, oenantholactam, decanolactam, undecanolactam,dodecanolactam, caproic 6-amino acid, 11-aminoundecanoicacid,12-aminododecanoic acid, diamine hexamethylene salts of adipic acid,azeleic acid, sebacic acid and 1,12-dodecanoic acid and the diaminenonamethylene salt of adipic acid, 2-aminocinnamic acid, L-asparticacid, 5-aminosalicylic acid, aminobutyric acid; aminocaproic acid;aminocapyryic acid; 1-(aminocarbonyl)-1-cyclopropanecarboxylic acid;aminocephalosporanic acid; aminobenzoic acid; aminochlorobenzoic acid;2-(3-amino-4-chlorobenzoyl)benzoic acid; aminonaphtoic acid;aminonicotinic acid; aminonorbornanecarboxylic acid; aminoorotic acid;aminopenicillanic acid; aminopentenoic acid; (aminophenyl)butyric acid;aminophenyl propionic acid; aminophthalic acid; aminofolic acid;aminopyrazine carboxylic acid; aminopyrazole carboxylic acid;aminosalicylic acid; aminoterephthalic acid; aminovaleric acid; ammoniumhydrogencitrate; anthranillic acid; aminobenzophenone carboxylic acid;aminosuccinamic acid, epsilon-caprolactam; omega-caprolactam,(carbamoylphenoxy)acetic acid, sodium salt; carbobenzyloxy asparticacid; carbobenzyl glutamine; carbobenzyloxyglycine; 2-aminoethylhydrogensulfate; aminonaphthalenesulfonic acid; aminotoluene sulfonicacid; 4,4′-methylene-bis-(cyclohexylamine)carbamate and ammoniumcarbamate.

Most preferably the material is selected from the group consisting of4,4′-methylene-bis-(cyclohexylamine)carbamate (commercially availablefrom R.T. Vanderbilt Co., Norwalk, Conn. under the tradename Diak® 4),11-aminoundecanoicacid, 12-aminododecanoic acid, epsilon-caprolactam;omega-caprolactam, and any and all combinations thereof.

In an especially preferred embodiment a nanofiller additive component inthe golf ball is surface modified with a compatibilizing agentcomprising the earlier described compounds having the general formula:(R₂N)_(m)—R′—(X(O)_(n)OR_(y))_(m),

A most preferred embodiment would be a filler comprising a nanofillerclay material surface modified with an amino acid including12-aminododecanoic acid. Such fillers are available from Nanonocor Co.under the tradename Nanomer 1.24TL.

Golf Ball Composition and Construction

Referring to the drawing in FIG. 1, there is illustrated a golf ball 1,which comprises a solid center or core 2, which may be formed as a solidbody of the herein described composition and in the shape of the sphere.

The core of the balls may have a diameter of from about 0.5 to about1.62, preferably from about 0.7 to about 1.60, more preferably fromabout 1 to about 1.58, yet more preferably from about 1.20 to about1.54, and most preferably from about 1.40 to about 1.50 in.

The core of the balls also may have a PGA compression of from about 30to about 200, preferably from about 35 to about 185, more preferablyfrom about 45 to about 180, and most preferably from about 50 to about120. In another embodiment, the core of the balls may have a PGAcompression of from about 30 to about 100, preferably from about 35 toabout 90, more preferably from about 40 to about 80.

In one embodiment the core may comprise the injection moldablepolyalkenamer rubber composition or polyalkenamer/polyamide compositionin the center and optionally, one or more core layers disposed aroundthe center. These core layers may be made from the same polyalkenamerrubber composition or polyalkenamer/polyamide composition as used in thecenter portion, or may be a different thermoplastic elastomer.

The various core layers (including the center) may each exhibit adifferent hardness. The difference between the center hardness and thatof the next adjacent layer, as well as the difference in hardnessbetween the various core layers may be greater than 2, preferablygreater than 5, most preferably greater than 10 units of Shore D.

In one preferred embodiment, the hardness of the center and eachsequential layer increases progressively outwards from the center toouter core layer.

In another preferred embodiment, the hardness of the center and eachsequential layer decreases progressively inwards from the outer corelayer to the center.

Intermediate Layer(s) and Cover Layer

Again referring to the drawing in FIG. 1, there is illustrated a golfball 1, which comprises a solid center or core 2, which may be formed asa solid body of the herein described composition and in the shape of thesphere, an intermediate layer 3, disposed on the spherical core and anouter cover layer 4.

The golf ball may comprise from 0 to 5, preferably from 0 to 3, morepreferably from 1 to 3, most preferably 1 to 2 intermediate layer(s).

In one preferred embodiment, at least one of the intermediate layerscomprises the novel blend compositions described herein.

In one preferred embodiment, the golf ball is a three-piece ball withthe injection moldable polyalkenamer/polyamide composition, orpolyalkenamer rubber composition, used in the intermediate or mantlelayer. In a more preferred embodiment the three-piece ball has aninjection moldable polyalkenamer/polyamide composition, or polyalkenamerrubber composition, used in the intermediate or mantle layer and a covercomprising a thermoplastic elastomer, a thermoplastic or thermosetpolyurethane or an ionomer.

In another preferred embodiment, the golf ball is a four-piece ball withthe injection moldable polyalkenamer/polyamide composition, orpolyalkenamer rubber composition, used in one of the two intermediate ormantle layers in the golf ball. In a more preferred embodiment thefour-piece ball has an injection moldable polyalkenamer/polyamidecomposition, or polyalkenamer rubber composition, used in the innermantle or intermediate layer. In an especially preferred embodiment, thefour-piece ball has an injection moldable polyalkenamer/polyamidecomposition, or polyalkenamer rubber composition, used in the innermantle or intermediate layer and a cover comprising a thermoplasticelastomer, a thermoplastic or thermoset polyurethane or an ionomer.

In another preferred embodiment, the golf ball is a four-piece ball withthe injection moldable polyalkenamer/polyamide composition, orpolyalkenamer rubber composition, used in one of the two intermediate ormantle layers in the golf ball. In a more preferred embodiment thefour-piece ball has an injection moldable polyalkenamer/polyamidecomposition, or polyalkenamer rubber composition, used in the outermantle or outer intermediate layer. In an especially preferredembodiment, the four-piece ball has an injection moldablepolyalkenamer/polyamide composition, or polyalkenamer rubbercomposition, used in the outer mantle or outer intermediate layer and acover comprising a thermoplastic elastomer, a thermoplastic or thermosetpolyurethane or an ionomer.

The one or more intermediate layers of the golf balls may have athickness of about 0.01 to about 0.50 or about 0.01 to about 0.20,preferably from about 0.02 to about 0.30 or from about 0.02 to about0.15, more preferably from about 0.03 to about 0.20 or from about 0.03to about 0.10, and most preferably from about 0.03 to about 0.10 orabout 0.03 to about 0.06 in.

The one or more intermediate layers of the golf balls also may have ahardness greater than about 25, preferably greater than about 30, morepreferably greater than about 40, and most preferably greater than about50, Shore D units.

The one or more intermediate layers of the golf balls may also have aflexural modulus from about 5 to about 500, preferably from about 15 toabout 400, more preferably from about 20 to about 300, still morepreferably from about 25 to about 200, and most preferably from about 30to about 100 kpsi.

The cover layer of the balls may have a thickness of about 0.01 to about0.10, preferably from about 0.02 to about 0.08, more preferably fromabout 0.03 to about 0.06 in.

The cover layer the balls may have a hardness Shore D from about 40 toabout 70, preferably from about 45 to about 70 or about 50 to about 70,more preferably from 47 to about 68 or about 45 to about 70, and mostpreferably from about 50 to about 65.

The COR of the golf balls may be greater than about 0.760, preferablygreater than about 0.780, more preferably greater than 0.790, mostpreferably greater than 0.795, and especially greater than 0.800 at 125ft/sec inbound velocity. In another embodiment, the COR of the golfballs may be greater than about 0.760, preferably greater than about0.780, more preferably greater than 0.790, most preferably greater than0.795, and especially greater than 0.800 at 143 ft/sec inbound velocity.

As described below in more detail, spheres of thepolyalkenamer/polyamide compositions may be made for the purposes ofevaluating their property performance. The compositions formed into suchspheres can have a PGA compression of from about 30 to about 200,preferably from about 35 to about 185, more preferably from about 45 toabout 180; a hardness Shore D from about 30 to about 85, preferably fromabout 40 to about 80, more preferably from about 40 to about 75; and aCOR greater than about 0.700, preferably greater than 0.710, morepreferably greater than about 0.720, and most preferably greater than0.730 at 125 ft/sec inbound velocity. In another embodiment, the spherescan have a COR greater than about 0.780, preferably greater than 0.790,more preferably greater than about 0.795, and most preferably greaterthan 0.800 at 125 ft/sec inbound velocity.

The polyalkenamer/polyamide compositions may have a flexural modulusfrom about 5 to about 500, preferably from about 15 to about 400, morepreferably from about 20 to about 300, still more preferably from about25 to about 200, and most preferably from about 30 to about 150 or 100kpsi; and a tensile elongation of at least about 10%, preferably atleast about 20%, more preferably at least about 30%, and most preferablyat least about 40%, at break.

Method of Making the Golf Balls

The polyalkenamer/polyamide composition or polyalkenamer rubbercomposition can be formed by any mixing methods. Thepolyalkenamer/polyamide composition or polyalkenamer rubber compositioncan be processed by any method such as profile-extrusion, pultrusion,extrusion, compression molding, transfer molding, injection molding,cold-runner molding, hot-runner molding, reaction injection molding orany combination thereof. The polyalkenamer/polyamide composition can bea blend of polyalkenamer and polyamide that is not subjected to anyfurther crosslinking or curing, a blend that is subjected tocrosslinking or curing; a blend that forms a semi- orfull-interpenetrating polymer network (IPN) upon crosslinking or curing,or a thermoplastic vulcanizate blend. The composition can be crosslinkedby any crosslinking method(s), such as, for example, applying thermalenergy, irradiation, or a combination thereof. The crosslinking reactioncan be performed during any processing stage, such as extrusion,compression molding, transfer molding, injection molding, post-curing,or a combination thereof. In one embodiment, the ability of thepolyalkenamer/polyamide compositions, or polyalkenamer rubbercomposition, to be injection molded and cured either subsequently bycompression molding or actually during the injection molding processitself provides considerable flexibility in manufacture of theindividual golf ball components.

For instance, the polyalkenamer/polyamide compositions, or polyalkenamerrubber composition, including crosslinking agents, fillers and the likecan be mixed together with or without melting them. Dry blendingequipment, such as a tumble mixer, V-blender, ribbon blender, ortwo-roll mill, can be used to mix the compositions. The golf ballcompositions can also be mixed using a mill, internal mixer such as aBanbury or Farrel continuous mixer, extruder or combinations of these,with or without application of thermal energy to produce melting. Thevarious components can be mixed together with the cross-linking agents,or each additive can be added in an appropriate sequence to the milledunsaturated polymer. In another method of manufacture the cross-linkingagents and other components can be added to the unsaturated polymer aspart of a concentrate using dry blending, roll milling, or melt mixing.

The resulting mixture can be subjected to, for example, a compression orinjection molding process, to obtain solid spheres for the core. Thepolymer mixture is subjected to a molding cycle in which heat andpressure are applied while the mixture is confined within a mold. Thecavity shape depends on the portion of the golf ball being formed. Thecompression and heat liberates free radicals by decomposing one or moreperoxides, which initiate cross-linking. The temperature and duration ofthe molding cycle are selected based upon the type of peroxide selected.The molding cycle may have a single step of molding the mixture at asingle temperature for fixed time duration.

For example one mode of preparation for the cores of the golf balls thatcomprise the polyalkenamer/polyamide composition, or polyalkenamerrubber composition, is to first mix the various core ingredients on atwo-roll mill or by extrusion to form slugs of approximately 30-45 g andthen compression mold in a single step at a temperature between 150 to210° C. for times between 2 and 20 minutes (or 2 and 12 minutes), toboth form the core and cure the polyalkenamer/polyamide composition, orpolyalkenamer rubber composition.

Alternatively, the core may be formed by first injection molding thepolyalkenamer/polyamide formulation, or polyalkenamer rubbercomposition, into a mold followed by a subsequent compression-moldingstep to complete the curing step. The curing time and conditions in thisstep would depend on the formulation of the polyalkenamer/polyamidecomposition, or polyalkenamer rubber composition, selected.

Alternatively, the core may be formed from the polyalkenamer/polyamidecomposition, or polyalkenamer rubber composition, in a single injectionmolding step in which the polyalkenamer/polyamide composition, orpolyalkenamer rubber composition, is injection molded into a heated moldat a sufficient temperature to effect either partially of fullycrosslinking the material to yield the desired core properties. If thematerial is partially cured, additional compression molding orirradiation steps may optionally be employed to complete the curingprocess to yield the desired core properties.

Similarly in both intermediate layer(s) and outer cover formation, theuse of polyalkenamer/polyamide compositions, or polyalkenamer rubbercomposition, allows for considerable flexibility in the layer formationsteps of golf ball construction.

For instance, finished golf balls may be prepared by initiallypositioning a solid preformed core in an injection-molding cavityfollowed by uniform injection of the intermediate or cover layerpolyalkenamer/polyamide-containing composition, or polyalkenamer rubbercomposition, sequentially over the core, to produce layers of therequired thickness and ultimately golf balls of the required diameter.Again use of a heated injection mold allows the temperature to becontrolled sufficient to either partially of fully crosslink thematerial to yield the desired layer properties. If the material ispartially cured, additional compression molding or irradiation steps mayoptionally be employed to complete the curing process to yield thedesired layer properties.

Alternatively, the intermediate and/or cover layers may also be formedaround the core or intermediate layer by first forming half shells byinjection molding the polyalkenamer rubber/polyamide compositions, orpolyalkenamer rubber composition, followed by a compression molding thehalf shells about the core or intermediate layer to effect the curing ofthe layers in the final ball.

Alternatively, the intermediate and/or cover layers may also be formedaround the core or intermediate layer by first forming half shells byinjection molding the polyalkenamer/polyamide compositions, orpolyalkenamer rubber composition, again using a heated injection moldwhich allows the temperature to be controlled sufficient to eitherpartially or fully crosslink the material to yield the desired halfshell properties layer properties. The resulting fully or partiallycured half shells may then be compression molded around the core or coreplus intermediate layer. Again, if the half shell is partially cured,the additional compression molding or irradiation steps may optionallybe tailored to complete the curing process to yield the desired layerproperties.

Finally, outer or intermediate covers comprising thepolyalkenamer/polyamide compositions, or polyalkenamer rubbercomposition, may also be formed around the cores using conventionalcompression molding techniques. Cover materials for compression moldingmay also be extruded or blended resins or castable resins.

In addition, if radiation is used as a cross-linking agent, then themixture comprising the unsaturated polymer and other additives can beirradiated following mixing, during forming into a part such as thecore, intermediate layer, or outer cover of a ball, or after formingsuch part.

The use of the novel blend compositions in the various components of agolf ball such as the core, intermediate layers and/or covers allows forincreases in COR and modulus in the materials of construction while alsoimproving the materials processability.

EXAMPLES

Examples are given below by way of illustration and not by way oflimitation.

Polyalkenamer Rubber Compositions

The materials employed in the blend formulations in Table 1 were asfollows:

VESTENAMER 8012 is a trademark of and commercially available from HulsAG of Marl, Germany, and through its distributor in the U.S., CreanovaInc. of Somerset, N.J., and is a trans-polyoctenamer having atrans-content of approximately 80% with a melting point of approximately54° C.

Surlyn® 8140 is a grade of ionomer commercially available from DuPont,and is a zinc ionomer of an ethylene/methacrylic acid polymer.

Surlyn® 9120 is a grade of ionomer commercially available from DuPont,and is a zinc ionomer of an ethylene/methacrylic acid polymer.

BR40 is a cis-1,4-polybutadiene rubber made with a rare earth catalystand commercially available from Enichem.

ZnO is a rubber grade zinc oxide purchased from Akrochem (Akron, Ohio).

ZDA are zinc diacrylates purchased commercially from Sartomer under thetradenames SR416, and SR638, which may be used interchangeably or incombination.

BaSO₄ is Poliwhite 200 barium sulfate purchased from Cinbar.

Varox 231-XL is 1,1-di(t-butylperoxy)-3,3,5-trimethyl-cyclohexanecross-linking initiator, (**40% active peroxide). This is commerciallyavailable from R.T. Vanderbilt and is made by Atofina.

Trigonox 145 is 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexynecross-linking initiator, (**45% active peroxide). This is commerciallyavailable from Akzo Nobel.

TAIC is triallyl isocyanurate, which is commercially available fromAkrochem.

Nanomer 1.24TL is a surface treated clay nanofiller, commerciallyavailable from Nanonocor Co.

Color concentrate is TiO₂ with ionomer as binder.

The properties of Tensile Strength, Tensile Elongation, FlexuralStrength, Flexural Modulus, PGA compression, COR, Shore D hardness onboth the materials and the resulting ball were conducted using the testmethods as defined below.

Core or ball diameter was determined by using standard linear calipersor size gauge. Core specific gravity was determined by electronicdensimeter using ASTM D-792.

Compression is measured by applying a spring-loaded force to the golfball center, golf ball core, or the golf ball to be examined, with amanual instrument (an “Atti gauge”) manufactured by the Atti EngineeringCompany of Union City, N.J. This machine, equipped with a Federal DialGauge, Model D81-C, employs a calibrated spring under a known load. Thesphere to be tested is forced a distance of 0.2 inch (5 mm) against thisspring. If the spring, in turn, compresses 0.2 inch, the compression israted at 100; if the spring compresses 0.1 inch, the compression valueis rated as 0. Thus more compressible, softer materials will have lowerAtti gauge values than harder, less compressible materials. Compressionmeasured with this instrument is also referred to as PGA compression.The approximate relationship that exists between Atti or PGA compressionand Riehle compression can be expressed as:(Atti or PGA compression)=(160−Riehle Compression).

Thus, a Riehle compression of 100 would be the same as an Atticompression of 60. Initial velocity of a golf ball after impact with agolf club is governed by the United States Golf Association (“USGA”).The USGA requires that a regulation golf ball can have an initialvelocity of no more than 250 feet per second±2% or 255 feet per second.The USGA initial velocity limit is related to the ultimate distance thata ball may travel (280 yards±6%), and is also related to the coefficientof restitution (“COR”). The coefficient of restitution is the ratio ofthe relative velocity between two objects after direct impact to therelative velocity before impact. As a result, the COR can vary from 0 to1, with 1 being equivalent to a perfectly or completely elasticcollision and 0 being equivalent to a perfectly plastic or completelyinelastic collision. Since a ball's COR directly influences the ball'sinitial velocity after club collision and travel distance, golf ballmanufacturers are interested in this characteristic for designing andtesting golf balls.

One conventional technique for measuring COR uses a golf ball or golfball subassembly, air cannon, and a stationary steel plate. The steelplate provides an impact surface weighing about 100 pounds or about 45kilograms. A pair of ballistic light screens, which measure ballvelocity, are spaced apart and located between the air cannon and thesteel plate. The ball is fired from the air cannon toward the steelplate over a range of test velocities from 50 ft/s to 180 ft/sec. As theball travels toward the steel plate, it activates each light screen sothat the time at each light screen is measured. This provides anincoming time period proportional to the ball's incoming velocity. Theball impacts the steel plate and rebounds though the light screens,which again measure the time period required to transit between thelight screens. This provides an outgoing transit time periodproportional to the ball's outgoing velocity. The coefficient ofrestitution can be calculated by the ratio of the outgoing transit timeperiod to the incoming transit time period, COR=T_(Out)/T_(in).

A “Mooney” viscosity is a unit used to measure the plasticity of raw orunvulcanized rubber. The plasticity in a Mooney unit is equal to thetorque, measured on an arbitrary scale, on a disk in a vessel thatcontains rubber at a temperature of 100° C. and rotates at tworevolutions per minute. The measurement of Mooney viscosity is definedaccording to ASTM D-1646. Shore D hardness was measured in accordancewith ASTM Test D2240. Hardness of a layer was measured on the ball,perpendicular to a land area between the dimples.

The ball performance may be determined using a Robot Driver Test, whichutilized a commercial swing robot in conjunction with an optical systemto measure ball speed, launch angle, and backspin after a golf ball ishit with a driver. In this test, a titanium driver is attached to aswing robot and the swing speed and power profile as well as teelocation and club lie angle is setup to generate the following valuesusing a Maxfli XS Tour golf ball as a reference:

-   -   Headspeed: 112 mph    -   Ballspeed: 160 mph    -   Launch Angle: 9 deg    -   Backspin: 3200 rpm

Then, the test ball is substituted for the reference ball and thecorresponding values determined.

In order to demonstrate the injection moldability of thepolyalkenamer-containing compositions a series of temperature versusviscosity curves were obtained using a Dynamic Mechanical Analyzer (DMA)and ASTM D4440 and these data are summarized in Table 1. As shown inTable 1, the viscosity of both a polyocetenamer (Vestenamer 8012) and atypical ionomer (Surlyn 8140) decreases with increasing temperature, asexpected for thermoplastic materials. However, when compared with atypical synthetic polybutadiene-based rubber (BR40), the polyocetenamerexhibits about an order of magnitude lower viscosity, which makes itpossible for melt processing (injection molding). The subsequentviscosity increase observed at temperature above 190° C. in the BR40 andpolyalkenamer samples is caused by breakage of unsaturated double bondsand subsequent propagation of crosslinking.

When peroxide (as a mixture of Varox 231XL and Trigonox 145) is added,there is an acceleration of crosslinking and a rapid increases inviscosity with temperature is observed as a result if this crosslinking,as is shown by the data in Table 1. Also, as a result of thiscrosslinking reaction, the COR of the polyalkenamer is significantlyimproved, such that it is significantly higher than that of most, if notall commercially available ionomers.

TABLE 1 Viscosity of Selected Compositions Viscosity (Pa-sec.)Temperature (C.) A B C D E 75 19,360 2,949 33,611 7,598 81 19,301 2,71632,240 6,960 85 19,537 2,493 30,277 6,191 91 19,341 2,314 27,873 5,70295 19,363 2,126 22,798 4,695 101 19,120 1,973 19,290 4,186 105 19,0591,826 16,514 3,766 111 18,777 1,700 16,987 3,643 115 18,682 1,580 24,5563,517 121 18,391 1,478 29,696 3,456 125 18,251 1,379 57,615 17,630 13117,949 1,292 73,539 36,344 135 17,768 1,211 119,000 139,000 141 17,4391,139 142,000 206,000 145 17,158 1,069 210,000 527,000 151 16,789 1,007243,000 747,000 155 16,405 946 313,000 1,870,000 161 16,014 893 329,0002,500,000 165 15,579 844 378,000 4,780,000 171 15,162 802 418,0005,710,000 175 14,557 762 1,295 614,000 9,000,000 181 14,139 732 976726,000 10,000,000 185 14,266 714 880 1,080,000 9,580,000 191 14,563 690745 1,240,000 7,730,000 195 15,593 696 665 1,590,000 5,680,000 20115,960 692 544 1,670,000 5,400,000 205 17,215 782 483 1,780,0004,870,000 211 17,779 806 404 1,760,000 4,820,000 215 19,740 933 3691,780,000 5,060,000 220 22,167 1,084 315 1,750,000 4,620,000 226 23,2761,263 288 1,760,000 230 26,918 1,471 247 1,740,000 235 31,265 1,703 225240 36,071 1,951 193 245 41,343 2,217 174 250 47,049 2,497 151 A: BR40B: Vestenamer 8012 C: Surlyn 8140 D: BR40-based compound includingperoxide. E: Vestenamer 8012-based compound including peroxide.

To further demonstrate the injection moldability of thepolyalkenamer-containing compositions the frequency versus storagemodulus (G′) profiles of a polyoctenamer (Vestenamer 8012) and a typicalsynthetic polybutadiene-based rubber (BR40) were obtained using aDynamic Mechanical Analyzer (DMA) and ASTM D4065, and ASTM D4440 at 25°C., and these data summarized in Table 2. Analysis of these data showsthat when compared with a typical synthetic polybutadiene-based rubber(BR40), the polyocetenamer exhibits a significantly higher storagemodulus (about two to three orders of magnitude higher) which results inprocessability sufficient for injection molding.

Three Piece Ball Examples

A series of three-piece (i.e., core, mantle, and cover) golf balls wereprepared. The balls were prepared to have a 1.480 inch commercialpolybutadiene rubber core made from a polybutadiene rubber (BR40) andfurther incorporating the crosslinkinking agents zinc diacrylate andperoxide and the filler zinc oxide, and prepared using traditional corecompression molding techniques with a mold temperature of 180° C. and acure time of 12 minutes. The resulting core physicals as summarized inTable 4. A mantle was injection molded over this core using compositionsincorporating Vestenamer 8012, marketed by Degussa Corporation. Thecompositions also incorporated crosslinkinking agents zinc diacrylateand peroxide and the filler zinc oxide as summarized in Table 3. Afterthe initial injection molding, the mantles were crosslinked in acompression mold at 180° C. for 12 minutes. A cover comprising a blendof 60 wt % Septon Hg252 and 40 wt % Surlyn 9120 was then injectionmolded over the mantle to yield a ball having the properties summarizedin Table 4.

Analysis of the date in Table 4 demonstrates that three-piece balls ofthe present invention, while having a low compression and low hardnessand thus having a soft feel or touch are also able to demonstrateexcellent COR and hence excellent distance.

TABLE 2 Storage Modulus of BR40 Rubber and Vestenamer 8012 StorageModulus, G′ (dyn/cm²) × 10⁵ Frequency (Hz) BR40 Vestenamer 8012 80.00067 5706 63.546 64 5632 50.477 62 5597 40.095 59 5572 31.849 57 554925.298 55 5530 20.095 53 5511 15.962 51 5491 12.679 49 5470 10.071 465447 8.000 44 5422 6.355 42 5398 5.048 40 5374 4.010 37 5349 3.185 355327 2.530 33 5303 2.010 31 5279 1.596 28 5260 1.268 26 5238 1.007 245214 0.800 22 5191 0.635 20 5167 0.505 19 5143 0.401 17 5118 0.318 155093 0.253 14 5068 0.201 13 5046 0.160 11 5028 0.127 10 5007 0.101 94988 0.080 8 4976 0.064 7 4970 0.050 7 4971 0.040 6 4974 0.032 5 49770.025 5 4987 0.020 4 4998 0.016 4 5011

TABLE 3 Three-Piece Ball Mantle Composition Data Mantle Compositions A BVestenamer 8012 100 100 ZnO 10 25 ZDA (SR416) 70 70 Varox 231XL 0.5 0.5Trigonox 145 0.14 0.14 * All values in pph

TABLE 4 Three-Piece Ball Physicals and Test Data Ex 1 Ex 2 Ex 3 Ex 4Core Composition A B C D Diameter(in) 1.420 1.480 1.420 1.480 CorePhysicals Core Compression 56 46 52 44 COR 0.827 0.82 0.83 0.823 SpG1.131 1.121 1.087 1.104 Mantle Composition A A B B Diameter(in) 1.6001.600 1.600 1.600 Thickness(in) 0.090 0.060 0.090 0.060 Mantled CorePhysicals Compression 64 54 65 55 Shore D Hardness 49 51 50 52 COR 0.8220.817 0.823 0.817 Cover Composition A A A A Thickness(in) 0.04 0.04 0.040.04 Ball Physicals Compression 69 66 70 66 Shore D Hardness 48 48 49 49COR @ 125 mph 0.814 0.812 0.816 0.814Four Piece Ball Examples

A series of four-piece (i.e., core, inner mantle, outer mantle, andcover) golf balls were prepared. The balls were prepared to have a 1.480inch commercial polybutadiene rubber core made from a polybutadienerubber (BR40) and further incorporating the crosslinkinking agents zincdiacrylate and peroxide and the filler zinc oxide, and prepared usingtraditional core compression molding techniques with a mold temperatureof 180° C. and a cure time of 12 minutes. The resulting core physicalsas summarized in Table 6. An inner mantle was injection molded over thiscore using compositions incorporating Vestenamer 8012, marketed byDegussa Corporation. The compositions also incorporated crosslinkinkingagents zinc diacrylate and peroxide and the filler zinc oxide assummarized in Table 5. After the initial injection molding, the mantleswere crosslinked in a compression mold at 180° C. for 12 minutes. Anouter mantle comprising a Surlyn 9120 followed by a cover comprising ablend of 60 wt % Septon Hg252 and 40 wt % Surlyn 9120 were thensequentially injection molded over the inner mantle to yield a ballhaving the properties summarized in Table 6.

TABLE 5 Four-Piece Ball Mantle Composition Data Inner MantleCompositions* A B C D E F G H I J Vestenamer 8012 100 100 100 100 100100 100 100 100 100 ZnO 20 20 20 20 ZDA (SR416) 80 70 70 60 60 50 60 6080 ZDA (SR638) 70 ZnPCTP 1 TAIC (triallyl 1 1 1 isocyanurate) Varox231XL 1.5 1.5 0.5 0.5 1.5 1.5 2.0 0.5 0.5 1.5 Trigonox 145 0.14 0.140.14 0.14 *All values in pph

Analysis of the date in Table 6 demonstrate that four-piece balls of thepresent invention, while having a low compression and low hardness andthus having a soft feel or touch, are also able to demonstrate excellentCOR and hence excellent distance.

TABLE 6 Four-Piece Ball Physicals and Performance Data Ex 5 Ex 6 Ex 7 Ex8 Ex 9 Ex 10 Ex 11 Ex 12 Ex 13 Ex 14 Polybutadiene core Core Size 1.4801.480 1.480 1.480 1.480 1.480 1.480 1.480 1.480 1.480 Core Compression57 57 65 49 63 53 53 68 57 49 COR 0.823 0.823 0.828 0.819 0.824 0.8190.819 0.828 0.822 0.819 SpG 1.148 1.148 1.143 1.134 1.161 1.164 1.1641.154 1.151 1.134 Inner mantle Vestenamer-based compound Diameter(in)1.580 1.580 1.580 1.580 1.580 1.580 1.580 1.580 1.580 1.580Thickness(in) 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.050 0.0500.050 Outer mantle Ionomer-based compound Diameter(in) 1.62 1.62 1.621.62 1.62 1.62 1.62 1.62 1.62 1.62 Thickness(in) 0.020 0.020 0.020 0.0200.020 0.020 0.020 0.020 0.020 0.020 Cover Ionomer blend Thickness(in)0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 Ball PhysicalsCompression 75 75 77 72 74 70 69 72 71 71 Cover Hardness 51 50 52 51 5251 49 50 51 50 COR @ 125 mph 0.816 0.817 0.821 0.815 0.82 0.815 0.8160.818 0.814 0.809

Polyalkenamer/Polyamide Compositions

The materials employed in the blend formulations in Table 7 were asfollows:

VESTENAMER 8012 is a trademark of and commercially available from HulsAG of Marl, Germany, and through its distributor in the U.S., CreanovaInc. of Somerset, N.J., and is a trans-polyoctenamer having atrans-content of approximately 80% with a melting point of approximately54° C.

GRILAMID TR90 is commercially available from EMS Chemie and is acopolymer of dodecanedioic acid with4,4′-methylenebis(2-methylcyclohexanamine) (also known ascyclohexanamine, 4,4′-methylenebis(2-methylcyclohexanamine) having aglass transition temperature (T_(g)) of 155° C., specific gravity of1.01, flexural modulus of 229 kpsi, flexural strength of 11,900 psi,tensile strength at yield of 8,300 psi, and a tensile elongation of 150%at break.

GTR45 is commercially available from EMS Chemie and is a polyamide 61Thaving a glass transition temperature (T_(g)) of 127° C., specificgravity of 1.18, flexural modulus of 460 kpsi, flexural strength of17,900 psi, and a tensile elongation of 135% at break.

Surlyn® 6120 is a grade of ionomer commercially available from DuPont,and is a zinc ionomer of an ethylene/methacrylic acid polymer.

The properties of Tensile Strength, Tensile Elongation, FlexuralModulus, PGA compression, COR, Shore D hardness on the materials wereconducted using the test methods as defined below.

Tensile Strength was measured in accordance with ASTM Test D 368.

Tensile Elongation was measured in accordance with ASTM Test D 368.

Flexural Modulus was measured in accordance with ASTM Test D 790.

Compression is measured by applying a spring-loaded force to the sphereto be examined, with a manual instrument (an “Atti gauge”) manufacturedby the Atti Engineering Company of Union City, N.J. This machine,equipped with a Federal Dial Gauge, Model D81-C, employs a calibratedspring under a known load. The sphere to be tested is forced a distanceof 0.2 inch (5 mm) against this spring. If the spring, in turn,compresses 0.2 inch, the compression is rated at 100; if the springcompresses 0.1 inch, the compression value is rated as 0. Thus morecompressible, softer materials will have lower Atti gauge values thanharder, less compressible materials. Compression measured with thisinstrument is also referred to as PGA compression. The approximaterelationship that exists between Atti or PGA compression and Riehlecompression can be expressed as:(Atti or PGA compression)=(160−Riehle Compression).Thus, a Riehle compression of 100 would be the same as an Atticompression of 60.

Initial velocity of a golf ball after impact with a golf club isgoverned by the United States Golf Association (“USGA”). The USGArequires that a regulation golf ball can have an initial velocity of nomore than 250 feet per second±2% or 255 feet per second. The USGAinitial velocity limit is related to the ultimate distance that a ballmay travel (280 yards±6%), and is also related to the coefficient ofrestitution (“COR”). The coefficient of restitution is the ratio of therelative velocity between two objects after direct impact to therelative velocity before impact. As a result, the COR can vary from 0 to1, with 1 being equivalent to a perfectly or completely elasticcollision and 0 being equivalent to a perfectly plastic or completelyinelastic collision. Since a ball's COR directly influences the ball'sinitial velocity after club collision and travel distance, golf ballmanufacturers are interested in this characteristic for designing andtesting golf balls.

One conventional technique for measuring COR uses a golf ball or golfball subassembly, air cannon, and a stationary steel plate. The steelplate provides an impact surface weighing about 100 pounds or about 45kilograms. A pair of ballistic light screens, which measure ballvelocity, are spaced apart and located between the air cannon and thesteel plate. The ball is fired from the air cannon toward the steelplate over a range of test velocities from 50 ft/s to 180 ft/sec. As theball travels toward the steel plate, it activates each light screen sothat the time at each light screen is measured. This provides anincoming time period proportional to the ball's incoming velocity. Theball impacts the steel plate and rebounds though the light screens,which again measure the time period required to transit between thelight screens. This provides an outgoing transit time periodproportional to the ball's outgoing velocity. The coefficient ofrestitution can be calculated by the ratio of the outgoing transit timeperiod to the incoming transit time period, COR=T_(Out)/T_(in).

Shore D hardness was measured in accordance with ASTM Test D2240.

The compositions described herein can be prepared by using a twin screwextruder with or without pre-mixing prior to charging to the extruder.The barrel temperature for the blending may be between about 140° C. toabout 300° C., more preferably between about 160° C. to about 280° C.,and most preferably between about 180° C. to about 260° C. Thecompounded material can be positioned readily around a golf ball coreusing injection molding. The barrel temperature for the injectionmolding may be between about 160° C. to about 280° C., more preferablybetween about 180° C. to about 260° C., and most preferably betweenabout 200° C. and 260° C.

The blends were prepared by using a twin screw extruder with or withoutpre-mixing prior to charging to the extruder. The barrel temperature forthe blending was Feed Zone 50° C., Barrel Zones 200° C. and Die Zone255° C. Test specimens were made from the blends by injection molding.Spheres were made from the blends by injection molding. The blendingredient amounts are shown in parts per hundred (pph).

TABLE 7 A B C D E F G H I J Material Composition TR90 100 100 100 100100 GTR45 100 100 100 Vestenamer 8012 10 15 20 30 10 20 100 Surlyn 6120100 Specimen Properties Tensile Strength (psi) 6460 5595 6749 8008 4815887 Tensile Elongation (%) 50 115 30 42 113 75 Flexural Modulus (kpsi)197 184 320 375 69 24 Sphere Properties* Shore D Hardness 80 72 71 70 6880 74 86 68 42 Compression 173 176 176 174 171 182 179 184 159 109 COR0.829 0.799 0.785 0.768 0.736 0.803 0.763 0.86 0.758 0.576

The results in Table 7 demonstrate that the toughness (durability) ofpolyamide has been significantly improved by blending with atrans-polyoctenamer. As seen in Table 7, addition of atrans-polyoctenamer increases tensile elongation (TE) from 50%(composition A) to 115% (composition B), which is nearly the same TE asSurlyn 6120 (composition I). In addition, a composition that includesonly polyamide (composition A) had a Shore D hardness of 80, but addinga polyoctenamer to the composition (compositions B, C, D and E)advantageously reduced the Shore D hardness while unexpectedlymaintaining the COR in a suitable range. Moreover, the ionomercomposition (composition I) exhibited a COR of 0.758 which is consideredin the art to be a superior result. Surprisingly, the non-ionomer blends(compositions B, C, D, G and H) advantageously resulted in higher CORscompared to the ionomer composition (composition I).

In view of the many possible embodiments to which the principles of thisdisclosure may be applied, it should be recognized that the illustratedembodiments are only preferred examples and should not be taken aslimiting the scope of the invention.

1. A golf ball comprising: (a) a core comprising a center; (b) an outercover layer; and (c) one or more intermediate layers; wherein at leastone of the core, or the intermediate layer comprises a composition thatincludes at least one polyalkenamer and at least one polyamide, whereinthe polyamide comprises a polyamide elastomer.
 2. The golf ball of claim1, wherein the composition comprises an injection moldable rubbercomposition that includes at least one polyalkenamer and at least onepolyamide.
 3. The golf ball of claim 1, wherein the polyamide elastomercomprises a thermoplastic copolyamide.
 4. The golf ball of claim 3,wherein the thermoplastic copolyamide comprises a polyether amideelastomer or a polyetherester amide elastomer.
 5. The golf ball of claim3, wherein the thermoplastic copolyamide comprises polyamide 12 as apolyamide segment.
 6. The golf ball of claim 1, wherein the polyamide isa major ingredient of the composition.
 7. A golf ball according to claim1, wherein the composition comprises about 10 to about 98 wt % polyamideand about 2 to about 90 wt % polyalkenamer, based on the final weight ofthe composition.
 8. The golf ball according to claim 7, wherein thecomposition comprises about 40 to about 90 wt % polyamide and about 10to about 60 wt % polyalkenamer, based on the final weight of thecomposition.
 9. The golf ball of claim 1, wherein the polyamideelastomer comprises a reaction product of copolycondensation of at leastone polyamide block having reactive chain ends with at least onepolyether block having reactive chain ends selected from: (a) apolyamide block having a diamine chain end with a polyoxyalkylenesequence of dicarboxylic chains; (b) a polyamide block havingdicarboxylic acid chain ends with a polyoxyalkylene sequence havingdiamine chain ends obtained by cyanoethylation and hydrogenation ofpolyoxyalkylene alpha-omega dihydroxylated aliphatic sequences; (c) apolyamide block of dicarboxylic chain ends with polyether diols; or (d)any combination or mixture thereof.
 10. The golf ball of claim 1,wherein the polyamide elastomer comprises a reaction product ofpolycondensation of the components: (a) a diamine and a dicarboxylate,lactame or an amino dicarboxylic acid; (b) a polyoxyalkylene glycol; and(c) an aromatic dicarboxylic acid.
 11. The golf ball of claim 1,comprising an inner intermediate layer comprising a polyalkenamer rubbercomposition, and an outer intermediate layer comprising the compositionthat includes the at least one polyalkenamer and the at least onepolyamide elastomer.
 12. A four piece golf ball comprising: (a) a corecomprising a center; (b) an outer cover layer; (c) an inner intermediatelayer comprising a unimodal ionomer, a bimodal ionomer, a modifiedunimodal ionomer, a modified bimodal ionomer, a polyalkenamer; or anyand all combinations or mixtures thereof; and (d) an outer intermediatelayer comprising an injection moldable composition comprising at leastone polyalkenamer and at least about 10 weight percent of at least onepolyamide, based on the total polymer amount of the outer intermediatelayer.
 13. The golf ball of claim 12, wherein the injection moldablecomposition comprises at least about 60 weight percent polyamide. 14.The golf ball of claim 12, wherein the outer cover layer comprises athermoplastic elastomer, a thermoset polyurethane, a thermoplasticpolyurethane, a unimodal ionomer, a bimodal ionomer, a modified unimodalionomer, a modified bimodal ionomer; or any and all combinations ormixtures thereof.
 15. The golf ball of claim 12, wherein the outer coverlayer comprises: A) one or more triblock copolymers; or one or morehydrogenation products of the triblock copolymers; or one or morehydrogenated diene block copolymers; or mixtures thereof; wherein eachtriblock copolymer has (i) a first polymer block comprising an aromaticvinyl compound, (ii) a second polymer block comprising a conjugateddiene compound, and (iii) a hydroxyl group located at a block copolymer,wherein each hydrogenated diene block copolymer has apolystyrene-reduced number-average molecular weight of from 50,000 to600,000 and is a hydrogenation product of (i) an A-B block copolymer, inwhich A is an alkenyl aromatic compound polymer block, and B is either(1) a conjugated diene homopolymer block, wherein the vinyl content ofthe conjugated diene portion is more than 60%, or (2) an alkenylaromatic compound-conjugated diene random copolymer block wherein thevinyl content of the conjugated diene portion is 15-60%, or (ii) anA-B-C block copolymer, in which A and B are as defined above and C is analkenyl aromatic compound-conjugated diene copolymer tapered block,wherein the proportion of the alkenyl aromatic compound increasesgradually, or (iii) an A-B-A block copolymer, in which A and B are asdefined above, and wherein in each of the hydrogenated diene blockcopolymers, the weight proportion of the alkenyl aromatic compound toconjugated diene is from 5/95 to 60/40, the content of the bound alkenylaromatic compound in at least one block A is at least 3% by weight, thetotal of the bound alkenyl aromatic compound contents in the two blockA's or the block A and the block C is 5% to 25% by weight based on thetotal monomers, and at least 80% of the double bond unsaturations of theconjugated diene portion is saturated by the hydrogenation; and B) oneor more ionomers.
 16. The golf ball of claim 12, wherein the outer coverlayer comprises the reaction product of: at least one component Acomprising a monomer, oligomer, or prepolymer, or polymer comprising atleast 5% by weight of at least one type of functional group; at leastone component B comprising a monomer, oligomer, prepolymer, or polymercomprising less by weight of anionic functional groups than the weightpercentage of anionic functional groups of the at least one component A;and at least one component C comprising a metal cation, wherein thereaction product comprises a pseudo-crosslinked network of the at leastone component A in the presence of the at least one component B.
 17. Thegolf ball of claim 12, wherein the inner intermediate layer comprises aunimodal ionomer, a bimodal ionomer, a modified unimodal ionomer, amodified bimodal ionomer; or any and all combinations or mixturesthereof.
 18. The golf ball of claim 12, wherein the core comprises apolybutadiene, the outer cover layer comprises a polyurethane, and theinner intermediate layer comprises a unimodal ionomer.
 19. The golf ballof claim 13, wherein the core comprises a polybutadiene, the outer coverlayer comprises a polyurethane, and the inner intermediate layercomprises a unimodal ionomer.
 20. The golf ball of claim 12, wherein thepolyamide comprises a polyamide elastomer.
 21. The golf ball of claim20, wherein the polyamide elastomer comprises a polyether amideelastomer or a polyetherester amide elastomer.
 22. A method for making agolf ball comprising a core, one or more intermediate layers and anouter cover layer, wherein the method comprises: forming a blendcomprising at least one polyalkenamer rubber and at least one polyamide,wherein the polyamide comprises a polyamide elastomer; and injectionmolding the blend into a spherical mold to form the intermediate layer.23. The method of claim 22, further comprising maintaining the mold at atemperature such that essentially no crosslinking of the polyalkenamerrubber and polyamide occurs; and compression molding the layer resultingfrom the injection molding at a time, temperature and pressuresufficient to effect the desired degree of crosslinking or annealing ofthe polyalkenamer rubber.
 24. The method of claim 22, further comprisingmaintaining the mold at a temperature such that a desired degree ofcrosslinking or annealing of the polyalkenamer rubber and polyamideoccurs.
 25. The method of claim 22, wherein the polyamide elastomercomprises a polyether amide elastomer or a polyetherester amideelastomer.
 26. The method of claim 22, wherein at least about 60 weightpercent of the at least one polyamide is included in the blend, based onthe total polymer amount of the blend.
 27. A four piece golf ballcomprising: (a) a core comprising a center; (b) an outer cover layer;(c) an inner intermediate layer comprising a composition that includesat least one polyalkenamer and at least about 10 weight percent of atleast one polyamide elastomer, based on the total polymer amount of theinner immediate layer; and (d) an outer intermediate layer comprising aunimodal ionomer, a bimodal ionomer, a modified unimodal ionomer, amodified bimodal ionomer; a polyalkenamer; or any and all combinationsor mixtures thereof.
 28. The golf ball of claim 27, wherein thepolyalkenamer in the inner intermediate layer comprises a polyoctenamer.29. The golf ball of claim 27, wherein the outer intermediate layer ismade from an injection moldable composition that contains 60 to 100 wt %of the polyalkenamer, based on the final weight of the injectionmoldable composition.